Zoz GmbH is the core and the materials-company of Zoz Group and a globally operating manufacturer in mechanical process engineering with more than 20 years experience in this field. Focusing on nanostructured materials, Zoz GmbH is the worldwide market leader and a small but global player which does not only apply to equipment but also to nanostructured materials such as powder materials, coatings and bulk parts manufacturing by Mechanical Alloying and other High Kinetic Processing routes.
As the entire group, Zoz GmbH with it’s headquarter based in Wenden, Germany is an enterprise where competences match, connected by expertise, recognized requirements, intelligent synergies and straight philosophy from Materials Science via Process Engineering Technology up to finished Products serving niches and providing solutions professionally and globally.
So in example and in detail in one of the highest fields of expertise, Zoz GmbH is looking back on more than 15 years history in:
- development of advanced materials
- development of processing techniques to manufacture these materials
- development and manufacturing of the equipment to operate these processes
- use and/or offer materials and processing developments
- use and/or offer above named processing equipment
- manufacture and offer advanced materials
- consolidate advanced materials and offer bulk-parts
- design advanced materials in binder systems and offer paints and composites
- as well as recently development and manufacturing of Li-Ion Batteries and solid state H2-storage tanks
…where the interaction of equipment-manufacturing, materials-design and materials-production by using own equipment does lead to definite profitable process-engineered solutions and economically thought-out products and parts.
business responsibilities / highlights
Since decades we work on the design and production of drum(ball)mills that are basically used in industrial applications exclusively. This leads from porcelain-made or ceramic-lined (coated) mills for the chemical-, pharmaceutical-, food- and ceramic-industry, here in particular the production of paint-pigments, up to the processing of hard-phase materials which is usually performed in steel-mills often using hard-coated or lined vessels. Here also rubber-linings are applied.
The accessories for the drummills include charge-bearings, safety-valves and cooling- or heating systems. Related devices like screens/vibrating screens, magnetic filters, feeders, grinding media classification systems and agitated tanks are likewise designed and produced in-house. E.g. remarkable are here drain-strainer with auxiliary pipe and ring nozzle for ventilation in case of using drummills with porcelain pans and/or high-viscose and thixotropic slurries after wet milling.
Analogous to the since decades well-established agitated tanks, we now offer slurry-preparation-devices for RTU-enamel (ready to use) in particular for reasonable cost.
The produced vibrating screens were recently adjusted in one of their variants to the sieving of or high-viscose thixotropic slurries. This has been achieved by introducing a converter-drive and a varied drive-arrangement.
A here not inconsiderable however only in laboratory scale available special-design is the Ballmill BM* which is a drummill equipped with vacuum-airlocks and can therefore not only be operated under controlled atmosphere but also charged and discharged correspondingly.
The CM-Simoloyer®, MA/HEM/RM
Since about 11 years, we specialize next to the above products in the technology of Mechanical Alloying (MA).
The literature describes MA as repeated deformation, fracture and welding of powder particles by highly energetic ball collisions. This definition may be amplified in that MA stands out by the transfer of high leveled energy into powder and so Mechanical Alloying often leads to material transformation of the crystalline structure by solid state reactions. The Gibbs´ free energy is increased to higher levels during processing and results in mainly metastable states. Atomic dislocations, a high defect structure of the lattice, the immense magnification of the boundary surface and a high diffusion rate leads to low activation energies for those reactions.
A strict requirement is that during processing an inert atmosphere (inert gas or vacuum) can be maintained as then always new unsatisfied and therefore high reactive surfaces are created. By MA new materials with new properties can be synthesized that cannot be created by conventional route e.g. due to a not present thermal equilibrium or immiscibility of their components. Furthermore, materials properties can be influenced by above listed structural design (e.g. nanocrystalline and amorphous materials).
If the same technique is applied for particle size reduction and/or particle deformation of single-systems e.g. to receive a special particle geometry, this route is better described as High Energy (ball) Milling (HEM) and is in particular very suitable for the rapid production of ductile metal-flakes.
The definition of Reactive Milling (RM) is suitable if during milling a chemical respectively a chemical/physical reaction is wanted and observed. The advantage here can be an ultra-fine (nanoscaled) dispersion of particles/grains in a matrix of a multi-component system.
Recently, a new application field of this part became more and more relevant. This is the application of the high kinetic milling process for chemical synthesis with full yield and this without a liquid phase and most important, without any solvents, which gives this process application a very high environmental interest. By means of this kind of Reactive Milling, new covalent bindings (structures) from different components can be created in many areas of organic chemistry without waste. Furthermore, different molecular-complexes and organic salts can be produced quantitatively.
A strict separation of the 3 suggested categories is usually not applicable.
The above listed processing techniques are performed by a high kinetic milling process that often must be operated under complete inert-gas condition or vacuum. The equipment that we develop and produce for that and also use ourselves is called Simoloyer® and may be described as a high-kinetic horizontal-rotary-ballmill.
The major parameter for the kinetic energy input here is the maximum relative velocity of grinding media which in this case reaches a level of up to 14m/s. Due to the horizontal design as well as the application of Cycle Operation performed by the MALTOZ®-software, the definite disadvantageous caking-effect as known from the vertically designed devices is nearly impossible here. Due to the geometric design as well as the availability of corresponding and effective vacuum-airlock-systems, the so called dead-zones in the process do nearly not at all exist and the entire material-transfer as from charging to processing to discharging is to be performed under vacuum or inert gas relatively unproblematic and in any case safely guaranteed.
Here, an ongoing development is of major interest. To transfer these techniques to a continuously processing-mode, in general a carrier gas in a closed system is loaded outside the processing chamber with starting material, and after passing the same is separated and classified. In one of the available pilot-plants (see publication HKP of Enamel, part I), processes are currently applied that show a processing time below 10 minutes in batch-operation.
The accessories for the CM-Simoloyer include vacuum-airlock-systems, sample-units, container as well as container-tracks (manipulators) and grinding media handling systems for the larger industrial Simoloyer which is all and likewise designed and produced in-house. For the continuous systems, most important are carrier-gas-drives, solid-injection systems, cyclones and other separators as well as heat-exchanger and special-piping systems.
In October 1997 we had the opportunity to introduce the process of Mechanical Alloying (MA) which in this case is better described as High Energy Milling (HEM) into the first industrial application. Here in fact it is about a very successful production of copper and bronze flakes within 3 minutes processing time in a semi-continuous mode (see corresponding publication).
Today we are maybe the leading partner for high intensity milling processing (Mechanical Alloying, High Energy Milling, Reactive Milling) in laboratory as well as industrial scale.
Every day we work on developments on materials science, every two weeks at least one Pilot Testing Report is leaving the company that is directly related to applications in wear-resistance, cutting or tooling, hydride/de-hydride, shielding, radar adsorption, paint pigments and many others.
The HV-Simoloyer® are of a much lower kinetic than the CM-Simoloyer®. The drive-power is about 8 times lower and pretty much corresponds to the since decades known attritors and similar, sometimes identical devices of other producers.
Indeed the HV-Simoloyer cover corresponding applications in the range of low- and medium-kinetic processing and can be operated in horizontal as well as in vertical mode. Furthermore the grinding chamber can be turned 45 degrees over the vertical position. This can be done controlled during processing so that e.g. by means of cyclic turning +/- 45 degrees around the vertical axis, highly sensitive metal-flakes like platinum, silver or tantalum can be produced much more successfully as the problematic sinking effect of these materials during common vertical processing (dead zone due to gravity) can be compensated.
The HV-systems are designed correspondingly to the CM-Simoloyer so that all peripheral accessories in particular airlock-systems, containers and aerodynamic-flow-systems for sealing and /or semi-continuously processing can be used in horizontal as well as in vertical operation mode. That is why the HV-Simoloyer can be used without any problems under inert-gas, vacuum or closed fluid system which includes next to processing also charging and discharging of the product.
The at least 3 drives of the HV-Simoloyer fully communicate by means of the MALTOZ®-software so that the highest degree of automation is given.
The original motivation for designing the HV-Simoloyer has been insofar a fully reaction on the market in that there are considerable and apparent insuperable doubts on the part of the users to apply a new production route or principle for long term introduced and existing products, even under demonstrated considerable improvement of economically feasibility of products. In particular there are considerations that the changing from a vertically processing principle to a horizontally processing principle might have negative long-term-effects on the product. This barrier had to be noticed in particular difficult in case of the producers of paint-pigments for automotive paint industry (long-term-stability of pigments) as well as e.g. the producers of conductive pastes for computer-industry.
Laboratory-ballmill, rollermill, magnetic filter, glove-box, vacuum-furnace-tubes, pilot-cyclones, rotary vane feeders, solid injection systems, special valves, experimental units, coated/lined grinding media etc.
Because of the important business responsibility Research & Development in the field of materials science and process engineering, we run intensive laboratory operations. This for it’s part supplies a direct feedback to the business-area of processing-equipment development
The here followed philosophy is that those here needed external equipment that is not or not technically satisfying or economically questionable available on the market, that this kind of equipment is here examined according feasibility, improvement and economically more reasonable conception-possibility. This in fact and up to now has led to a number of new products that are all used also in our own laboratory operations.
In particular not inconsiderable are:
- compact and inexpensive laboratory-ballmill for separate or parallel operation of each 2 pairs of grinding vessels (4 in total);
- compact and inexpensive multi-rollermill for laboratory application;
- a number of various grinding vessels for laboratory-ballmill and rollermill which leads from a simple glass-bottle up to evacuation able containers with linings;
- magnetic filter based on modern magnetic material in magnetic-like design with approx. 1.5-2x higher magnetic-field-gradient and magnetic-field-strength than all other available to the cost of about 50 % at half needed space with impressive real-throughput, cleaning possibility and application-flexibility (funnels, pipe-line, pump-line etc.);
- fully suitable Glove-Box in different sizes with variable airlocks to about 50 % of the common market-cost;
- side channel turbines for KF-piping as well as heat-exchanger for multi-phase flows in such tube-systems;
- vacuum-furnace-tubes in particular for thermal extraction (degassing) of organic PCA’s from powder as well as heat-treatment of conductive metal-flakes for laboratory application;
- variable pilot-cyclones with standard-KF-ports as well as optical control for separation and classification of solid/gas-systems;
- laboratory-rotary vane feeders with standard-KF-ports for pressure-compensated transfer of powder material;
- solid injection systems with standard-KF-ports for charging powders or granules into aerodynamic systems;
- special-valves for dead-zone free charging or/and discharging of dry or liquid media out of respectively into processing-chambers under controlled condition at high throughput;
- special-units for KF-vacuum-tube-systems such as pipe switches, junction-tubes, pipe-bends, transparent pipe modules, glass- and steel-containers;
- experimental units for research & development projects, e.g. simulation unit CIBA (Cylinder in Bush Apparatus) of a continuously hot dip galvanizing/aluminizing plant including crucible, tractate-power- and metal-strip-velocity simulation as well as temperature control for comparing examination of new materials systems to be applied for bearing components in the liquid metal;
- coated grinding media, rubber-lined grinding media or e.g. Co-rich WC-Co-grinding media in particular for high-kinetic-processing application where for example common THM-grinding media collapses due to poor toughness;
The activities of Zoz GmbH in the field of R&D are mostly related to the sector of high kinetic processing which here means Mechanical Alloying (MA), High Energy Milling (HEM) and Reactive Milling (RM). The goal is most frequently the production of nano-structured, nanocrystalline and amorphous materials e.g. ODS-alloys, Composite-Materials or Highly Dispersed Phased Materials where highly-potential fields like Bearing-, Magnetic-, Contact-, Hydrogen-storage or for example Anticorrosion-Materials shall be served. The sector HEM is in particular focused on the development of rapid processing techniques for ductile-metal-flakes inclusive Particle-Coating and Particle-Bonding as well as rapid particle size reduction of solids.
Since R&D always causes considerable and at least short-term capital investment, we have to place as much of our goals as possible in public funded projects.
Highlight, potential revolution of enamel-processing
An out standing example how innovation in high-tech-sectors can reflect into conventional processing fields might be the high-kinetic-processing of enamel-frits on a mid-term range.
On the conventional route, rapidly solidified (quenched) glass-frits are discontinuously ground in ceramic-lined drum(ball)mills where after a milling-time of about 5-6 hours a particle size reduction down to 10-20 µm is reached.
In January 2000, for the first time we have been able to process glass-frits by High Energy Milling not in a batch but in a continuously route as of a size of about 6 mm in a processing time of 20-40 seconds (the real remaining time cannot be determined more exactly up to know) to a particle-size D50-value of 6 µm.
Since November 2001 we apply a continuously pilot plant VS01a based on a CM01 (see publication HKP of Enamel, part I), since August 2001 it has already been managed to adapt a production unit CM20.
The particle size distribution comes already pretty close to the quite large distribution as wanted and known for the conventionally produced standard-enamel – just the particles now are 3 times smaller at an approx. 650-900 times shorter processing time…
Characterization and analysis of the produced enamel-powder did show up a fully new and unexpected potential. Basically it can be expected, that in the future, the contamination problem caused by the processing itself, might be solved quantitatively which finally would mean, that in case of success, the today needed ceramic tools would not any longer be necessary and also the ceramic (alumina, accepted) contamination could be avoided.
In the sector of conventional equipment-development we here work at present on a preparation-device for RTU-enamel (ready to use) where the discrepancy of an agitator with a small working-surface and high surface-velocity needed for the preparation and an agitator with a large working-surface and a low surface-velocity needed for maintaining the dispersion is to be solved. Here also the possibility of an insofar diversion of preparation and maintaining is considered where for the preparation an injection-principle is examined for feasibility. Furthermore a corresponding enamel-spraying-tank with an interior agitator for maintaining is under conception.
Highlight, ductile metal flakes
Since the previous mentioned successfully Cu-flakes production in Japan, we focus on the use of our high kinetic process to explore and produce ductile metal flakes. At present we concentrate on the production based on Pt-, Pd-, Au-, Ag-, Cu-, Fe-, Ti-, Al- and Ni-powder for various applications. From our point of view, the most important application-areas are automotive-paints, conductive paints and pastes as well as anticorrosion coatings. With the new method, the production of flakes is possible within minutes in comparison to a processing time as of several hours up to several days.
A typical flake is here described as a particle with a thickness < 0.2 µm and a cross- or aspect-ratio of about 200 which refers to a diameter of 20 – 30 µm.
Almost exclusively in the entire world, our processing devices (Simoloyer) are used for investigation and pilot-production of nanocrystalline metal-hydrides.
Next to this it is well known, that metal-hydride storage systems have a far larger H-atom-storage-capability/volume as e.g. compressed, liquid or solid hydrogen itself has. Thus, the achievable atom-density in case of H-gas at 700 bar is approximately 3 times smaller than the by diffusion achievable H-atom-storage-capability/volume in case of a nanoscaled magnesium-hydride (MgH2). Simply spoken, a nanocrystalline structure of the material is needed in order to have a large surface of grain boundaries being used as diffusion highways for the H-atoms.
And since this technology is very interesting for many of our customers, it must also be interesting for us. This goes on the one hand for the equipment side as well as for the materials side on the other hand.
On challenge, that we face here, is the development of a Simoloyer that is not only operated, charged and discharged under inert gas or vacuum but finally under high pressure of hydrogen. Since early 2002 we are a member of the competence network fuel cells NRW in Germany and also here try to do our job as a little part of all to promote and drive a fast success of this future technology.
Mainly as a consequence of the flakes-production, at present we build up our first Atomizer (ZAT100) which is suitable for gas-atomization based on melt out of the crucible as well as droplet-melting with a vacuum-tube-manipulator. This device should have get on the market in the laboratory size as the Table-Top-Atomizer (ZAT50) in the year 2002. Furthermore we own one of the worldwide largest gas-atomizing systems (ZAT5000) with a free distance between nozzle and cone of approximately 5 meters where the diameter of the chamber is about 1 meter.
However, this project is put on hold since 2001 because priorities were to be decided different. The continuation is planned for summer 2002 by means of a co-operative project. Time schedule is moved for two years in minimum.
Early 1998 we started a small-scale powder production in our laboratory operations. For the execution of external jobs as well as for research projects, several Simoloyer (CM01, CM08 and CM20) in various types (e.g. chambers with heating system) with full staff equipment like air-locks, sample-units and glove-box are under operation. The production quantity of various and most frequently very special materials varies in the range up to 100 kg.
Usually external production jobs as well as pilot testing is covered by strict confidential agreements and is of course handled as such.
Furthermore we use a drummill (Comb03, laboratory scale, 30 liters) with various chambers which has up to now mostly been used for the processing of feedstock-materials for MIM.
Since September 2001 we have already our first own product series that is produced in co-operation with S&Z Anti-Corrosion Coatings Inc. in the US. These are Zn-powder grades SZ001, 002 and 003 which are used for zinc-rich coatings as anti-corrosion material.
Of course we have a specialist staff to carry out all needed powder/product characterization. However, due to high investment cost, most of the needed equipment (SEM/EDX, XRD, TEM, chemical analysis) is not available in-house. Here we have a very good and effective cooperation with our local university where our staff operates the corresponding investigations.
The foundation of the PM-parts-production at Zoz GmbH is related to the general-philosophy that an as complete as possible interconnection of an entire producing-process, which in case of powder metallurgy means the way from raw-powder-production via powder preparation and materials-design up to consolidation and if necessary, to machining, that such an interconnection, due to the extensive knowledge on each of the preceding and following single processing steps must insofar lead to an optimum service at least for the intermediate processing step.
The PM-parts-production is consequently not forced forward in large steps but is a new sector that is occupied if preceding processing steps here demand or originate this. So are results of a cooperative project being started in 1999 represented here by bearing bushes with a net-weight of 12 kg each and produced by Mechanical Alloying of Stellite®-based material, consolidated by HIP as well as LPS under HIP and finally machined and fitted on transfer-rolls. The consolidation here is not done in-house and shall not – at least in mid-term plan – be done so. The bearing bushes are used in the liquid metal bath of hot-dip galvanizing/aluminizing plants.
In March 2000 we introduced a new magnetic filter with an NdFeB-magnetic-core MK-078105 which is in principle a combination of powder metallurgy and conventional design. This part is already in series production, marketing is going rapidly and therefore it can be announced as our second PM-part already (a paper on this device, its development and its testing will be published at the next World-PM in summer 2002 in Orlando, together with one of the worldwide largest dental-ceramic producers).
The Software-department of Zoz GmbH develops Multimedia-Software for system-operation, system-control and process-control.
By means of the synthesis of decades of knowledge in mechanical engineering and modern software technology, advanced products highly oriented at the practical needs are created here, for the in-house needs (Simoloyer, Maltoz) as well as for external customers.
Next to precision and high performance, the intuitive user guiding is a remarkable feature of our software and is therefore easy and quickly to be learned.
Furthermore we are supplying advanced data-base-software for process-optimization to our customers.
The production facility of Zoz GmbH includes a wide capability of processing in mechanical engineering in general. Here e.g. lathe-working up to a diameter of 1480 mm is offered. Units up to 10 tons weight are handled.
The welding shop is equipped and perfectly familiar with all common devices therefore. In particular the company is specialized in working with stainless steels.
Major attention is not only focused onto the machinery but onto qualified and highly skilled workforce. In order to save this condition for the future, currently 5 young trainees are employed here.
Since the foundation of the company, a wide range of restore, rebuilding and repair of construction-units as well as single parts internal and external has been offered and done.
This of course includes improving, redesign and design of these units or parts. We are very proud to be announced as the house-and-home-supplier of two large Thyssen-Krupp-Stahl steelworks in our area.