Integrated Smart Materials Group

The new group is based on two fundamental technology fields, thermal spraying and non-destructive evaluation (NDE), which have been studied extensively in NIMS.
Thermal spraying has been usually used for a protective coating for harsh environment such as thermal barrier, corrosion and wear resistant coatings. However, recent new solid particle impact processes (cold spray and warm spray) make it suitable for an additive manufacturing tool.
NDE research activity in NIMS has been carried out fundamentally in detection of material degradation by various sensing techniques such as ultrasonic and laser-ultrasonic, terahertz wave technology, and X-ray computed tomography.
By fusing these two fields, additive manufacturing by particle integration process and sensing technologies by NDE, we aim to develop new smart materials with various sensing and protection functions. In future, we want to develop smart materials, which can sense degradation and failure in themselves and can prevent further damage evolution by themselves. With the aid of computation material science and data science, “materials integration”, we accelerate our research progress and challenge to develop innovative smart materials.

Specialized Research Field

1. Overview

Thermal spray is the most widely used and fairly versatile process to deposit thick overlay coatings, in which the raw materials tend to be degraded as they are melted and projected toward the substrates due to oxidation, for example, in the air atmosphere and a notable amount of pores are generally included. We have developed a novel spray process based on high-velocity impact of solid powder particles in a thermally softened state and named it as "Warm Spray". We have demonstrated the capability of the process by depositing highly dense coatings of titanium and WC-Co with little degradation in the air.

"Fig. Principle of Warm Spray process." Image

Fig. Principle of Warm Spray process.


"Fig. Cross sectional TEM image of warm sprayed Titanium particle on Aluminum substrate with FEM analysis result" Image

Fig. Cross sectional TEM image of warm sprayed Titanium particle on Aluminum substrate with FEM analysis result


"Fig. Comparison of the microstructure and properties of WC-Co cermet coatings deposited by conventional HVOF spray and Warm Spray methods. Warm sprayed coating exhibits finer and uniform microstructure resulting in higher hardness and smoothness." Image

Fig. Comparison of the microstructure and properties of WC-Co cermet coatings deposited by conventional HVOF spray and Warm Spray methods. Warm sprayed coating exhibits finer and uniform microstructure resulting in higher hardness and smoothness.




2. Process analysis and modeling

Even with the same raw material and same process, resultant coatings can have widely different microstructures and properties. Due to the unique nature of the deposition process, the process-structure-property relationships of sprayed coatings are not fully established. We have been accumulating data and knowledge at various scales starting from impact of single sprayed particle, internal structure of single splat, AE measurement during deposition as well as the in-situ measurements of strains and stresses during spraying. Through developing these analysis and instrumentation with various collaborators, we aim to facilitate fundamental understanding of thermal spray processes and improve their reliability.

"Fig. Fundamental research on processing of thermal barrier coatings (TBC) covering from single particle impact to macroscopic coating deposition." Image

Fig. Fundamental research on processing of thermal barrier coatings (TBC) covering from single particle impact to macroscopic coating deposition.




Group Leader

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1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, JAPAN
E-Mail: KURODA.Seijinims.go.jp
National Institute for Materials Science (NIMS)
1-2-1 Sengen, Tsukuba, Ibaraki 305-0047, JAPAN
TEL.+81-(0)-29-859-2000
FAX.+81-(0)-29-859-2029