ICMCTF2003 Session G2: Scale-up, Manufacturing Aspects and Industrial Applications
Tuesday, April 29, 2003 1:30 PM in Sunrise
G2-1 Market Implementation of New Cathodic Arc Deposition Technologies, from Ideas to Successful Industrial Solutions
A. Korenyi-Both (Plasma and Vacuum Technologies, LLC); H. Curtins (SwissPlas.com, Switzerland); H. Gabriel (Plasma und Vakuum Technik, GmbH, Germany); J. Thiele (United Coating Technologies, LLC); H. Mathies (NewPlas,com, Switzerland)
We have developed a novel deposition platform that yields operational and coating performance levels not seen before in the Hard Coating Industry. Many opportunities exist for proper performance to application correlation, choosing the correct laboratory and field tests, and properly evaluating the results. A strong focus is placed on the economics of implementing novel deposition technologies and infrastructure related issues in order to insure success. Coating system size as related to scaling processes from research to development to viable industrial solutions is carefully considered. Realistic throughput and operational cost calculations were implemented for successful market impact.
G2-3 Effective Nitrogen Diffusion Coefficient During the Early Stages of Post-Discharge and Plasma Nitriding
J.E. Oseguera, O. Salas, J.L. Bernal, U. Figueroa, F. Castillo (ITESM, Mexico)
A model for nitrogen transport from the surface into the solid during the initial stages of plasma-assisted nitriding of ferrous materials is presented. The description is based on the estimate of an effective diffusion coefficient during these initial stages that considers the microstructural features of the incipient nitrides. The model then predicts the time required to initiate the formation of nitrides and explains the features of their subsequent growth. Pure iron and carbon steel samples were nitrided for very short times by microwave post-discharge and ion nitriding. The microstructure of the samples was extensively characterized. Distinctive nitride morphologies within the grains and along the grain boundaries were observed as well as preferred nitride orientations and abundant grain-boundary precipitation. The size and distribution of initial nitrides was also determined. The microstructural observations have helped discern the most likely diffusion mechanism during the early stages of nitriding. An effective diffusion coefficient has been considered to describe the nitrogen mass transfer from the grain and through the grain boundary during the early nitriding stages. The effective diffusion coefficient is compared to the diffusion coefficient during growth of compact concomitant nitride layers.
G2-4 Tribological Behavior of Coatings and Surface Treatments in Severe Die-Casting Production Conditions - Part 1: Glow Discharge Ion Nitriding
V. Joshi, A Srivastava, R. Shivpuri (Ohio State University); E. Rolinski (Advanced Heat Treat Corp.)
Die-casting dies are exposed to extreme corrosive environment during a typical die casting operation using aluminum alloys. The corrosive action is governed by the solubility of the die material (often H-13) in the molten aluminum alloy and is controlled by the composition of the cast metal and the die steel, and causes "soldering" in die- casting. To protect die surfaces from these actions, surface treatments and thin film ceramic coatings applied by PVD and techniques have been evaluated using both laboratory tests and production evaluation. @paragraph@ The controlled laboratory test is a very good tool to compare different surface treatments and coatings but they fail to provide the accurate life predictions of a particular coating. This is due to the major differences in the environmental and processing conditions of the lab test and the actual production conditions.@paragraph@ This paper shares the results of the performance of nitriding surface treatment in a detailed test campaign conducted at a participating die casting company. These results are then compared and contrasted with the controlled laboratory test results. This paper is the first paper in the series of two papers on the behavior of well-engineered surface treatments and coating systems in actual production environment.
G2-5 Tribological Behavior of Coatings and Surface Treatments in Severe Die-Casting Production Conditions - Part 2: Multilayer PVD LAFAD Coatings
V. Joshi, A Srivastava, R. Shivpuri (Ohio State University); S.J. Dixit (UES, Inc.); R. Bhattacharya (UES,Inc.)
Die-casting dies are exposed to extreme corrosive environment during a typical die casting operation using aluminum alloys. The corrosive action is governed by the solubility of the die material (often H-13) in the molten aluminum alloy and is controlled by the composition of the cast metal and the die steel, and causes "soldering" in die- casting. To protect die surfaces from these actions, surface treatments and thin film ceramic coatings applied by PVD and techniques have been evaluated using both laboratory tests and production evaluation. @paragraph@This paper is the second paper in the series of two papers on the behavior of well-engineered surface treatments and coating systems in actual production environment. The paper 1 of this series, details the effect of nitriding surface treatment on the behavior of H-13 steel in laboratory and production conditions. @paragraph@This paper shares the results of the performance of engineered multilayer PVD coatings in a detailed test campaign conducted at a participating die casting company. These results are then compared and contrasted with the controlled laboratory test results. It has been observed in these tests that, the engineered multilayer PVD coatings increase the life of the tool steel by a factor of 4 to 5 times with the substantial savings in downtime cost.
G2-6 Scale-up and Commercialization of Combustion CVD Technique
A.T. Hunt (MicroCoating Technologies, Inc.)
The Combustion Chemical Vapor Deposition (CCVD) and NanoSpray(SM) process developed by MicroCoating Technologies (MCT) offer a novel way to synthesize coatings of metals, oxides and polymer composites in open atmosphere, allowing greater flexibility in enabling next-generation products used in wireless, nanomaterials, barrier, electronics, and superconductor applications. The CCVD process is an environmentally friendly, low-cost process that can deposit a wide range of oxides and some metals in the open atmosphere. The NanoSpray process can form nanopowders, and deposit polymers thin films. Significant efforts have enabled the research and development of the CCVD process to go from bench top to the manufacturing of coated wire, sheet, wafer and formed products.@paragraph@ The substrates used with both processes include polymers, metals, ceramic materials or composites and the source material are predominantly liquid solutions and low-cost precursor materials such as nitrates, acetates, and 2EH. These solutions are formed into submicron sized droplets by the use of MCT’s proprietary Nanomiser® device. The submicron-sized droplets, when entrained into the combustion flame, enter into a vapor state and then condensate onto the substrate. Numerous compositions have been deposited epitaxially onto various substrates and the process is not line-of-sight limited. Over 100 different materials have been deposited, most with multiple cations - all using the same deposition system. Due to the use of this single deposition system, with easy to change/blend liquid solution sources, new material systems can be developed rapidly. @paragraph@ The Nanomiser device is also being applied for cleaner burning fuels and chemical processing. Commercialization of MCT's technology has taken place during 2002. The business model employed varies with the industry and includes licensing or selling components and materials.
G2-8 Putting Coatings Into Practice: Qualification of Thermal Spray Coatings to Replace Hard Chrome on Functional Components
B.D. Sartwell (US Naval Research Laboratory); K.O. Legg (Rowan Technology Group)
In 1996, the U.S. Department of Defense formed the Hard Chrome Alternatives Team (HCAT) which had the objective of qualifying HVOF thermal spray coatings to replace hard chrome plating in manufacturing and maintenance operations on military aircraft. Because of the widespread use of hard chrome on different types of components, separate projects were established for landing gear, propeller hubs, gas turbine engine components and hydraulic actuators. Because each involved flight critical components, the direct involvement of all stakeholders in identifying the types of tests required to qualify the HVOF coatings for production was essential. Technical issues that arose during testing also had to be addressed to the satisfaction of the stakeholders. This presentation will review the significant amount of materials (fatigue, wear, corrosion) testing and component evaluations that have been conducted, what technical issues arose, and how those issues are being addressed. The methodology that has led to success in implementing HVOF technology at military repair depots will be discussed.
G2-9 Physical Powder Deposition of Solid Lubricant Nanoparticles by Electrostatic Spray Coating (ESC)
W. Jiang, A.P. Malshe, W.D Brown (University of Arkansas)
Nanoparticles are essential building blocks of bottom-up manufacturing of nanostructured porous as well as dense coatings with unique properties such as ultrahigh hardness, strength, and wear resistance. During deposition, using nanoparticles as raw material, particles are prone to cluster and tend to stick to the surfaces in physical contact. These tendencies impose a major challenge to delivery and coating of nanoparticles via traditional techniques. In this paper, a successful physical powder deposition technique, namely electrostatic spray coating (ESC) for large and complex surface geometries is presented for the coating of solid lubricant sub-micron and nanosized particles of MoS@sub 2@ and ZnO. The presentation further discusses the coating mechanism through response of the nanoparticles to the static electric field and carrier gas flow.
G2-10 Investigation of Laser Engineered Net Shaping (LENS@super TM@ Deposited Tungsten Coatings on H13 Tool Steel for Squeeze Casting
J. Brevick, P. Collins, J. Harm, S. Joshi (Ohio State University)
A common problem in aluminum squeeze casting is failure of squeeze pins via soldering. Squeeze pins are 10 to 20 mm diameter pins that are retracted and flush with the die cavity when molten aluminum fills the cavity. After a short time, the pins are inserted into the solidifying casting under high pressure for the purpose of eliminating shrinkage porosity in load critical areas of the casting. Soldering occurs when aluminum metallurgically bonds to squeeze pin surfaces and prevents the pins from retraction upon opening of the die and ejection of the solidified casting. The result is typically pin breakage, with ensuing downtime required to replace pins.@paragraph@ PVD and CVD applied thin hard coatings on traditional high pressure die casting dies and core pins have been extensively studied and show tremendous potential for preventing soldering. However, thin coating success for squeeze pin applications has been limited because of the high temperature, pressure and additional mechanical loading they experience in service. This research investigates the use of Laser Engineered Net Shaping (LENS') technique deposited tungsten coatings in improving the soldering resistance of the squeeze pins. The research was conducted with the assumption that a relatively thick layer (~350 µm) of tungsten, which is known to resist soldering by aluminum, would be able to withstand the mechanical loads and yield superior performance in squeeze pin service.@paragraph@ H13 squeeze pins were tungsten coated via the (LENS') technique, the coatings characterized metallurgically, and pin performance evaluated via a dip-style soldering test in molten aluminum.
G2-11 A Computational Design Approach to Engineer Surface Treatment of Dies for Resistance Against Thermal Fatigue Cracking
A Srivastava, R. Shivpuri (Ohio State University)
Thermal fatigue cracking leads to die failure and major loss in production in forging and die casting industries. It is caused by the thermal stresses developed due to alternate heating and cooling of die surface. Since, the thermal loading changes from die to die and also within different regions of a die, there cannot be a single treatment all processing conditions. This paper presents an approach to engineer surface treatment of dies for resistance against thermal fatigue resistance, depending on the tribological and thermomechanical conditions present at the die-material interface. An FEM based thermal fatigue model is used to analyze the thermal stresses and strains and to suggest the required properties of the surface treatment- die material pair to withstand those stresses and temperatures. This approach is evaluated in simulated laboratory experiments and verified in actual production conditions. Results of laboratory and industrial experiments with engineered coatings are included in this paper.