Executive Summary

The ATP Focused Program, Tools for Engineered Surfaces, is being proposed to help industry overcome several high-risk technical barriers and make a paradigm shift from a point solutions approach to a structured approach in the development of new materials, processes, or components. The goal of this program will be to (1) simultaneously improve engineered surface process designs and reduce cost through reduced development time and increased yield and consistency; and (2) develop prime reliant surfaces which are integral to the design and operation of a component, as opposed to mere life enhancement. The strategy for meeting that goal will be the development of a set of manufacturing and analytical process tools which are applicable to materials which provide wear, corrosion and thermal enhancements to substrates, and which exploit new developments in process diagnostics (including in-line process control and non-destructive evaluation); life / performance prediction (including innovative modeling and simulation); and equipment design and development.

Definitions

Opportunity being addressed

Engineered surfaces are critical to the performance of many commercial products. Contact with industry and academia in the Surface Engineering community has suggested that, due to individual priorities and availability of resources, today's approach to surface development tends to be empirical and specific to a component and/or materials system. As a result, industrial knowledge consists of sets of point solutions--this has made it difficult to develop new opportunities that are not very similar to a previous application, since the more general problems of process design and scale-up, performance prediction and material development, have not been addressed. Our discussions and working group meetings with the surface engineering community would suggest that an ATP focused program in surface engineering should offer the opportunity to shift the industry from point solutions to a structured approach, ultimately moving the status of surface modification from life enhancement to prime reliancy.

Background

Engineered surfaces are critical to the performance of many commercial products. For example, most of the components in a typical jet engine or motor vehicle are surface engineered in some manner, whether through heat treating, texturing, coatings, or some other form of surface engineering. The vast majority of engineered surfaces are developed empirically for specific components and materials, and tend to represent an incremental improvement. A few of the processes involved to fabricate these engineered surfaces include chemical vapor deposition (CVD), physical vapor deposition (PVD), plasma spray, and ion implantation. Material examples include diamond films for cutting tools, titanium nitride on wear surfaces, and zirconia thermal barrier coatings on turbine blades.

Potential for U.S. Economic Benefit

Potential benefits from engineered surfaces are very wide spread since they affect almost all industries to some extent. Several representative industries in which engineered surfaces are critical are listed in Table I. For these industries, the total value of 1995 product shipments was $524.56B, with a total of 9,524 establishments with 1,458,200 employees. Table II indicates that these industries consume almost $25B in materials, a significant percentage of which are surface engineered. Table III lists several supporting industries, with a total value of product shipments of $35.23B in 1995.

In addition to those industries listed in Table I, other large industries also employ engineered surfaces, such as printing, textiles, and pulp and paper.

In order to determine the potential benefits of technical success in an engineered surfaces program, one would consider both the effect on the products listed above, as well as the effects on the markets for the coatings themselves. Some information on just a few coating techniques is shown in Table IV. These are values of worldwide shipments, which indicate that the worldwide values for CVD, PVD, implantation, and epitaxy coatings was $8.7B, projected to grow to $15.2B by 2000. It should be noted that a significant percentage of this market is controlled overseas. According to BCC, Inc., the value of the U.S. ceramic coatings (materials only) market is $564M, with an annual growth rate of 7.4%.

Battelle Laboratories performed a 1995 update of a 1978 NBS study on the cost of metallic corrosion in the U.S.--they estimated this at $300B/year (4.2% of GNP). Of this amount, $104B was considered avoidable. Studies have also been performed on the cost of wear to the U.S.--two examples are cutting tool wear at $900M/yr (in 1975 dollars) and automotive maintenance and repair (much of which can be attributed to wear) at $40B/year (in 1975 dollars)--the cost of wear today is in the neighborhood of the cost of corrosion. Engineered surfaces are key to the reduction of avoidable corrosion and wear. A focused program in tools for engineered surfaces will enable a dual path--on the earlier path, current material systems will gain increased performance and reliability; on the later path, the knowledge base for the development of new and better systems to combat corrosion (or other issues) will be built.

Source: DOC Bureau of Census, 1995 Annual Survey of Manufactures, *1992 Census of Manufactures

Source: DOC Bureau of Census, 1992 Census of Manufactures

Source: BCC, Inc. Thin Layer Deposition Technologies, 1996

Good Technical Ideas

Successful proposals will present high risk innovative approaches to the development of tools for engineered surfaces, all with the larger goal of reduced cost and greater performance (through greater reliability, uniformity, and batch-to-batch consistency) shorter development time, and prime reliancy. Some of the general areas within which solutions may be developed include plasma diagnostics, in-situ monitoring and control, structure-function modeling, simulations and prediction, scalability of design, controlled low temperature or atmospheric processing, non-destructive evaluation, improved torches, and others. A few examples of innovative ideas follow.

Process Diagnostics: Point of Deposition Monitors, Controls, and Models

The understanding of processes, in-situ, is extremely important in being able to develop consistency and reliability over time in a product. Sophisticated plasma diagnostics are now being developed and could aid in this endeavor. The development of on-deposit sensors based on the intrinsic response of complex oxides (such as perovskites) to temperature, stress and environment offers the potential to measure critical parameters. These sensing elements may be imbedded in solid prototypes of actual components to be coated or produced as printed circuits on test substrates. They may also be developed as "witness" condition sensors--a novel concept to measure conditions at the site of deposition without interfering with the deposition site itself. Research required includes determination of appropriate oxide compositions, understanding of response to deposition parameters, and methods of fabrication and data handling in cost-effective ways. The verification of process models which allow scale up is critical to evolution of models as well as development of credibility which ensures their use. Positron emission monitoring of reactive species distribution demonstrated in catalytic system design in universities in the United Kingdom and the Netherlands may provide such a means but has been unproven at elevated temperatures.

The cleanliness of a surface is only now beginning to be understood, yet it has a profound effect on the performance of a coating. An innovative cleanliness monitor has been theorized which could be developed by using plasma to excite species on the surface--wavelength emissions could yield information about the conditions. A study of this nature would also include a definition of sufficiently "clean."

Interfaces are being tailored by utilizing dual plasma sources (concurrent processes) to control the distribution of heat input during processing. The functions of the plasma would be separated, one providing heat for deposit chemistry control and the other to heat the substrate (and to change the structure of the boundary layer).

Equipment Design: Plasma Spray Torch Design

More precise control will be needed in order to significantly increase the reliability and uniformity of coating. Significant aspects of torch design which are limitations to control and process repeatability include understanding of the behavior of injected coating materials and electrode erosion prediction and control. The key to improvement lies in the ability to model and measure the three dimensional time dependent behavior of these high temperature, turbulent systems.

A general model applicable to all torch manufacturers has been called for and would allow the rapid introduction of new processes, such as high rate deposition of nano materials. For example, hypersonic plasma particle deposition, HPPD, involves the feeding of reactants into a plasma, and the formation of nanoparticles. This process has a deposition rate of 1 um/second and is potentially useful for the formation of nanostructured surfaces, as well as freeform fabrication. Feasibility has been demonstrated, but consistent, uniform coatings with sufficient film adhesion or wear resistance have not been fabricated.

Life / Performance Prediction

The performance of engineered surfaces to allow transition from being a performance enhancement to a reliable part of a component requires predictive tools which relate processing to properties to performance. The methodology for this has been initiated for gear steels. These monolithic models are less complex than the bi-material engineered surface systems which typically include metastable, anisotropic materials. Models which range from atomistic to continuum features are being considered in finite element analysis (FEA) designs used by the engineering community. Conceptual approaches and the isotropic models provide a starting point.

Source: DOC Bureau of Census, 1992 Census of Manufactures

Table VII. Demonstration of world distribution of Engineered Surface Technology through the issuance of U.S. Patents, and Presentations at the largest Applied and Basic Research Meetings

Technical and Business Scope with Inclusions and Exclusions

Included in the scope of this program will be projects that target the creation of a set of tools which are applicable to materials which provide wear, corrosion and thermal enhancements to substrates and which directly lead to prime reliance for at least one material/application combination. These tools will fall into at least one of the following categories:

• Process diagnostics (including in-line process control and non-destructive evaluation)
• Life / performance prediction (including innovative modeling and simulation)
• Equipment design and development

All projects in this program will address the development and validation of a high risk innovative tool which is potentially applicable to more than one material and application.

Exclusions

• Tools meant specifically for the application of paint
• Tools related specifically to heat treating
• Tools meant specifically for microelectronics
• New materials and processes for their own sake

Date created: January 1999
Last updated: April 12, 2005