ICMCTF2004 Session G1: Innovations in Surface Coatings and Treatments

Tuesday, April 20, 2004 1:30 PM in Room Sunrise

Tuesday Afternoon

Time Period TuA Sessions | Abstract Timeline | Topic G Sessions | Time Periods | Topics | ICMCTF2004 Schedule

Start Invited? Item
1:30 PM G1-1 Improved Coating Properties and Optimized Substrate Data, Essential Conditions for High Performance Cutting Tools
K.-D. Bouzakis, G. Skordaris, S. Hadjiyiannis, N. Michailidis (Aristoteles University of Thessaloniki, Greece); G. Erkens, R. Cremer (CemeCon AG, Germany)

Innovative PVD coatings led to a significant reduction of wear and friction and to a tremendous increase in performance of modern cutting tools. Hereupon numerous coating and substrate parameters should match and have to be adapted best to a particular application in order to meet the elevated demands of modern manufacturing procedures. Such parameters are the tool macro and micro geometry, the substrate data and especially the superficial mechanical properties and topomorphy, the coating system, the deposition process technology etc.

In the present paper the effect of some of the previously mentioned parameters, on the coated tool wear behaviour will be demonstrated and explained with the aid of finite elements method (FEM) based simulations of the cutting process. In these FEM calculations the coating elasto-plastic and fatigue properties are required. These data are extracted through nanoindentations and impact tests respectively, as it will be described. Coating and substrates internal stress alterations, during tool micro-blasting or annealing procedures occurring, have to be considered and can be detected effectively by means of nanoindentations and an algorithm developed, to evaluate the corresponding measurements results.

2:10 PM G1-3 About the High Ionization Pulsing Technology and its Application to Deposite Crystalline PVD Alumina
R. Cremer, G. Erkens, T Hamoudi (CemeCon AG, Germany)
During the last years crystalline PVD alumina has been considered to be the next step to further improve the performance of meta-stable (Ti,Al)N based coatings. Especially the crystalline modifications deposited with CVD technique have gained considerable economic significance for turning and milling applications. All developments in the area of coating processes have been always closely related to efforts of reducing the deposition temperatures. Different approaches led to the possibility to deposit crystalline alumina with PVD at a temperature range of 500-700°C on cutting inserts and shank tools. Distinct chemical resistance, higher hot hardness than most hard coatings and the fact that crystalline alumina has less interaction with most production relevant materials than most other hard coatings are the key factors to develop the PVD technology for the deposition of crystalline alumina coatings. The High Ionization Pulsing (H.I.P.) PVD process to deposit crystalline alumina and the influence of the sputtering conditions on the properties will be illustrated. The investigated alumina coatings were deposited reactively by sputtering aluminum in an Argon/Oxygen atmosphere. The deposited films were evaluated by metallographical examinations and first results from metal cutting tests will be presented.
2:30 PM G1-4 High Performance AlTiN Coatings Deposited by Arc Technology
M. Arndt (METAPLAS IONON GmbH, Germany)
The Arc technology is most qualified for deposition of high performance coatings for cutting tools. Especially AlTiN Arc coatings have proven their outstanding properties in many high demanding cutting processes. Due to their excellent adhesion, high hardness, extremely smooth surface and nanocrystalline morphology combined with a superior oxidation resistance AlTiN-Saturn coatings are in favor for sophisticated applications. For example in high speed and high performance cutting operations the possible avoidance of coolants means an important contribution to environment protection. This paper deals also with the influence of different pretreatments like microblasting or stripping processes on the properties of AlTiN-Saturn. Furthermore, the possible dependency of coating behaviour on different doping elements is investigated.
2:50 PM G1-5 Tribological Coatings and Their Implemented Applications.
R. Tietema, C. Strondl (Hauzer Techno Coating BV, The Netherlands); G.J. Van der Kolk (Bodycote, The Netherlands)
The intention of this paper is to give an overview of the different kinds of tribological coatings that are available on the market. From the coatings that will be discussed in the paper, the specific coating properties in some field applications will be shown. Focus will be on Me-DLC coatings, DLC-coatings as well as on Cr-based coatings, as these coatings can be found back in many different automotive applications.
3:30 PM G1-7 Ion Implantation of Superhard Ceramic Cutting Tools
K. Chou, J. Liu (The University of Alabama)
Despite numerous reports of tool life increase by ion implantation in machining operations, ion implantation applications of cutting tools remain limited, especially for ceramic tools, yet mechanisms of tool life improvement by implantation are not clearly established because of complexity of both implantation and tool wear processes. In an attempt to improve performance of cubic boron nitride (CBN) tools for hard machining by ion implantation, a literature survey of ion implanted cutting tools was carried out with focus on mechanisms of tool wear reduction by ion implantation. Implantation and machining experiments were then conducted to investigate implantation effects on CBN tools in hard machining. A batch of CBN tools has been implanted with nitrogen ions at 150 keV and 2.5*10(17) ions/cm2, and further used to cut 61 HRc AISI 52100 steel at different conditions. Results show that ion implantation has strong effects on part surface finish, moderate on cutting forces, but insignificant on tool wear. Friction coefficients, estimated from measured cutting forces, are possibly reduced by ion implantation, which may improve surface finish. However, surprisingly, 2-D orthogonal cutting to evaluate tribological loading in hard machining showed no difference on contact stresses and friction coefficients between implanted and nonimplanted CBN tools.
3:50 PM G1-8 Oxide Barrier Coatings on Steel Strip by Spray Pyrolysis
R. Lopez, J.R. Ramos Barrado, F. Martin, D. Leinen (Universidad de Malaga, Spain)

ZnO, TiO2 and ZrO2 thin films have been deposited by chemical spray pyrolysis onto differently galvanized steel strips (ThyssenKrupp Steel) for its potential use as protective layer against degradation due to ambient impact during long term outdoor exposure. The steel strips shall be used as base material for unglazed solar collectors and must thus comply including all its overcoats (oxide barrier-, selective-, antireflection layer) with manufacturing requirements for collectors as moulding, forming, cutting, etc. (EU project: SOLABS)1. In order to improve the so-called weatherability of the galvanized steel strip by overcoating it with an oxide barrier layer, conditions as total substrate coverage, high compactness and an optical transparency better than 90% of the oxide barrier layer have to be fullfilled. These oxide barrier layers have been produced by spraying adequate aqueous precursor solutions, using air as driving gas, onto the heated steel substrate (T<300ºC) where pyrolysis takes place and the corresponding oxide layer grows. In this communication we present a comparative study of the morphological, structural, chemical and optical properties of these oxide layers (ZnO, TiO2, ZrO2) deposited by spray pyrolysis on three types of galvanized steel substrates. Results from complementary analytic techniques as SEM, XRD, XPS and UV/VIS/IR spectroscopy demonstrate that highly compact and thin oxide layers can be produced by spray pyrolysis protecting the steel. We would like to stress that after a preselection of the most adequate oxide barrier material, upscaling to large surfaces and high speed deposition is intended as required in a conventional coil coating technique. Furthermore we would like to mention that chemical spray pyrolysis, using air as driving gas and aqueous precursor solutions, is an environmentally friendly and, since working under ambient atmosphere, inexpensive deposition technique.

1 http://www.solabs.net/.

4:10 PM G1-9 Surface Properties and Mechanical Behavior of Electro-plasma Coatings
P. Gupta, E.O. Daigle, G. Tenhundfeld (CAP Technologies, LLC)
Electro plasma process (EPP) is a novel tool for cleaning and coating of conductive materials. EPP is environmentally friendly and exhibits improved surface characteristics and corrosion resistance. This technology has shown great promise in various industrial applications. The present study involves coating of steel rods and plates with Zn and Ni coatings, using EPP. Microstructure analysis was performed to determine the grain size of coatings. Surface profile and morphology of coatings was studied by optical profilometer and SEM, respectively. Microhardness studies were conducted using Knoop's indenter at 50 gmf and 100 gmf load. Microhardness tests were conducted on surface and cross section of the coated specimens. The results were compared to the steel coating applied by conventional industrial processes. An attempt has been made to develop a overall understanding of the processing-structure-property relationship of the EPP coatings.
4:30 PM G1-10 Recent Developments in Surface Technology in Germany
G. Bräuer (Fraunhofer Institute of Electron Beam and Plasma Technology, Germany); R. Fellenberg (VDI Technology, Germany)

Plasma surface engineering has become a key technology in Germany during the past two decades. Today plasma based processes are widespread in various industrial branches. They are used by 50% of German companies being active in the field of machine construction. A further growth is limited by high costs and a qualification deficiency. Nevertheless, a lot of companies, in particular small and medium sized enterprises plan to introduce new processes or modernize existing ones within the next two years.

New developments focus on tribological coatings like diamond-like carbon (DLC) and cubic boron nitride (c-BN). Pulse magnetron sputtering has opened the door to new applications of optical coatings on large areas. Solar cell manufacturers ask for low cost deposition of semi-conducting thin films and transparent conductive oxides. Concerning the field of information technology, high performance mirrors for EUV lithography and ultra thin carbon overcoats for magnetic disks are in the centre of interest.

5:10 PM G1-12 Duplex Treatment of Autenitic Stainless Steel for Improved Corrosion and Wear Resistance
A. Hurkmans, A. Hieke (Bodycote Coating Centrum BV, The Netherlands); M. Waegner (Bodycote Hardiff BV, The Netherlands)
Austenitic Stainless Steel is a material that is frequently used in the medical and chemical industry. The combination of strength and relative high corrosion resistance is a favourable set of properties. Under specific conditions it is desirable to further increase the corrosion resistance (in chloride environments) and wear resistance. The untreated stainless steel is quite soft (approximately HV200) and shows strong tendency to adhesive wear within tribological pairs. The PVD (Physical Vapour Deposition) technology offers a wide range of hard coatings to increase the wear resistance (for example metalnitrides) and to modify the interaction between two counterparts (for example carbon based coatings). Such hard and brittle coatings fail under large deformations (egg-shell effect) when deposit on relative soft substrates. This paper reports on a carbon diffusion layer for austenitic stainless steel that supports the W-C:H coating as deposited by PVD. The diffusion process avoids carbide formation and corrosion resistance is not lost, even improved. Results for untreated stainless steel, stainless steel with a carbon diffusion layer (approximately 20 micrometer, HV1000), stainless steel with W-C:H (approximately 3 micrometer, HV1500), and the duplex treatment are discussed. The corrosion resistance is measured by neutral salt spray testing. The mechanical properties are a result of micro-hardness testing, scratch adhesion testing, pin-on-disc testing, and kalo-wear testing.
Time Period TuA Sessions | Abstract Timeline | Topic G Sessions | Time Periods | Topics | ICMCTF2004 Schedule