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

这个小型企业技术转移(STTR)第一阶段项目将开发两个新型快速沉积速率传感器的原型，这两个传感器将实现等离子喷涂的实时沉积速率控制。目前，等离子喷涂相对于实际颗粒状态是开环运行的，其特点是变化大，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度没有很好的相关性。新的传感器概念使用高速CCD阵列测量颗粒通量，使用光谱反卷积测量熔体通量，两者都已被证明与沉积速度有很好的相关性。这些新型高速传感器将为实施实时控制提供基础，从而显著减少涂层厚度变化，这是等离子喷涂的主要性能指标。等离子喷涂是一种高通量、经济、低环境影响的工艺，可用于定制涂层微观结构，以满足特定的性能要求。它被广泛用于在涡轮机部件上涂覆热障涂层(全球市场价值25亿美元，其中美国占有35%的市场份额)以及新兴应用，如燃料电池的电解液涂层。该项目提出的能够进行实时控制的传感器技术，将增强等离子喷涂的工艺能力，使其达到2西格玛以上的能力，提高涂层质量和可靠性，并缓解国内制造商面临的部分成本压力。

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.