STTR Phase I: Novel Deposition Rate Sensors for Real-Time Thickness Control of Plasma Spray

这项小型企业技术转移（STTR）第一阶段项目将开发两种新型快速沉积速率传感器的原型，从而实现对等离子喷涂的实时沉积速率控制。等离子体喷射目前是开环运行，相对于实际粒子状态，其特点是有很大的变化，影响产量和质量。初步研究表明，目前可用的测量平均粒子温度和速度的传感器与沉积速率没有很好的相关性。新的传感器概念使用高速CCD阵列来测量粒子通量，使用光谱反褶积来测量熔融通量，这两者都被证明与沉积速率有很好的相关性。这些新型高速传感器将为实现实时控制提供基础，可以显著减少涂层厚度变化，这是等离子喷涂性能的主要指标。等离子喷涂是一种高通量、经济、低环境影响的工艺，可用于定制工程涂层微结构，以满足特定的性能要求。它被广泛用于涡轮部件的热障涂层（全球市场为25亿美元，其中美国占有35%的市场份额）以及新兴应用，如燃料电池的电解质涂层。本项目提出的传感器技术，能够实现实时控制，将提高等离子喷涂的工艺能力，达到大于2 σ的能力，提高涂层质量和可靠性，缓解国内制造商面临的一些成本压力。

This Small Business Technology Transfer (STTR) Phase I project will develop prototypes of two novel, fast deposition rate sensors that will enable implementation of real-time deposition rate control for plasma spray. Plasma spray is currently run open loop with respect to the actual particle states and is characterized by large variations which affect yield and quality. Preliminary research reveals that currently available sensors, which measure average particle temperature and velocity, are not well correlated to deposition rate. The new sensor concepts measure particle flux using a high speed CCD array and molten flux using spectral deconvolution, both of which have been shown to correlate well to deposition rate. These new high speed sensors will provide the basis for implementing real time control that can significantly reduce coating thickness variation, a primary plasma spray performance metric.Plasma spray is a high-throughput, economical, low environmental impact process that can be used to custom engineer coating microstructure to meet specific performance requirements. It is used extensively to coat turbine components with thermal barrier coatings (world wide market of $2.5 B where US has a 35% market share) as well as emerging applications such as the electrolyte coating for fuel cells. The sensor technology proposed in this project, enabling real-time control, will enhance the process capability of plasma spray to achieve greater than 2 sigma capability, enhancing coating quality, reliability and relieving some of the cost pressures faced by domestic manufacturers.