Cavitation erosion (CE) damage, which occurs in the main parts (made of high chromium cast steel) of hydroelectric power generation machine, is one of the serious problems. It is expected that life time of those parts would be prolonged if the suitable CE-resistant coating is applied on the surface of the cast steel. In this study, WC-cermet coatings (WC-CoCr and WC-Cr 3 C 2 -Ni), which were fabricated by high-velocity oxygen-fuel (HVOF) thermal spraying process, was interested in protecting CE attack to the cast steel. To clarify CE property of the WC-cermet coatings, the ultrasonic vibration tests were conducted, and the amount of volume loss characterized as CE damage was measured. The microstructure and the fracture toughness, which was evaluated by the indentation test method, of the coatings were related with the CE damage. As the results obtained in this study, the fragment which was spalled from the surface after CE test was almost flake-like shape, and its size was from 2µm to 50µm. SEM observation indicated that this fragment included both WC particle and metal binder, which means that WC particle and metal binder was still strongly bonded together. It was also confirmed that the amount of volume loss could relate directly with the fracture toughness KIC rather than Vickers hardness. It was considered that CE damage was progressed into the depth by throwing out the fragment originated from micro crack initiation. Thus, it was required that the CE resistance of the developed coatings could be labelled through the fracture toughness.

This paper presents a method, based on push-rod type thermomechanical analysis, for determining the thermal expansion behavior of thermal barrier coatings (TBCs). It shows that TMA measurements can provide accurate CTEs for yttria-stabilized zirconia layers as thin as 0.3 mm with good reproducibility and low measurement error (< 5%). The method was also used to assess the effect of annealing on thermal expansion behavior, revealing a slightly monotonic decrease in the CTE of YSZ samples.

“Testing Method for Heat Resistance under Temperature Gradient” is a Japanese Industrial Standard (JIS) newly established by the Minister of Economy, Trade and Industry, after deliberations by the Japanese Industrial Standards Committee, in accordance with the Industrial Standardization Law. This standard specified the testing method for heat resistance under temperature gradient of materials and coated members of equipment exposed to high temperature, such as aircraft engines, gas turbines, reciprocating engines, accelerators, power switchgears etc. Three kinds of testing method, such as burner heating test, arc heating test and various beam heating tests are involved.

This paper describes a failure analysis that effectively combined multiple analytic techniques to find the cause of I/O leakage in a flawed chip produced for an OEM (Original Equipment Manufacturer) product. Internal probing was initially used for defect isolation and a Tungsten (W) stud open circuit flaw was isolated by electrical characterization with internal probing. SEM (Scanning Electron Microscopy), TEM (Transmission Electron Microscopy, and FE-AES (Field Emission Auger Electron Spectroscopy) analysis with FIB (Focused Ion Beam) preparation were used for physical analysis. Cross-sectional SEM and TEM observations showed a gap with foreign material (FM) between the bottom of the metal line and the top of the W stud, possibly from the W CMP (chemical mechanical polish) process. FE-AES is effective for the analysis of light materials and their chemical composition, so a flat milling FIB process was used to prepare a cross-section for FE-AES analysis of the FM and the interfaces of the open defect. The spectra showed that the FM was traceable to the W CMP process. From these analytical results and problem reproduction experiments in the W CMP process on the manufacturing line, the failure mechanism was identified.

A new analysis method using conventional emission microscopy (EMS) was developed for localizing open defects in CMOS LSIs. EMS is widely used for failure analysis of IDD (power supply current) leakage failures. The root cause of a failure is deduced by considering the emission characteristics associated with the IDD leakage current, emission shape, emission energy spectrum, and exact location on an Si die. Our new technique focuses on the observation of transient photoemission immediately after VDD application. During IDD leakage failure analysis, unique transient photoemission characteristics are observed. Immediately after VDD application, strong photoemission is briefly observed at the drain edge of an n-FET, but disappears after stabilization of the IDD current. We assumed that temporary photoemission would not be generated in transient behavior unless some kind of open defects were located at a specific conductor connected to the gate electrode. This mechanism was verified by nonbiased charge-up contrast of a conventional secondary electron image (SEI) and cross-sectional SEM observation at the defective open location. The dynamic method of observing transient photoemission proposed here is a very effective and practical way for detecting the locations of open failures in CMOS LSIs. Some examples of open mode failure analysis are described, along with cross-sectional TEM observations.