This study assesses the microstructure and mechanical properties of tungsten boride (WB) powder and cemented carbide coatings with WB additions. HVOF-sprayed layers produced from 60WC-30WB-10Co composite powders are compared with conventional 88WC-22Co and 86WC-10Co-4Cr coatings based on phase composition, hardness, wear resistance, and wear surface structure. The results indicate that Co reacts with WB during spraying, forming ternary phases (WCoB, W 2 CoB 2 ) that increase hardness as well as sliding wear resistance.

Nanostructured WC-CoCr powder was prepared and deposited on carbon steel substrates by HVOF spraying. The coatings obtained were characterized based on phase constitution, elemental distribution, and microstructure as well as corrosion and sliding wear behaviors. X-ray diffraction was used to identify the main phase constituents and EDS analysis revealed the distribution of Co and Cr in the coating. The mechanisms involved in the formation of microstructure are discussed along with the effects of Cr on coating performance.

Previous studies have shown that nanostructured coatings produced by plasma spraying can stimulate cellular activity and promote bone healing. Since then, a number of studies have been conducted to better understand how coating nanotopography can be controlled and how it influences bioactivity and healing. This paper reviews some of the key findings in three areas: the effects of nanotopography on bone cell adhesion, the effects of nanotopography on bone-like apatite formation in simulated body fluid, and how to refine the nanotopography of plasma-sprayed coatings.

A nanostructured WC-CoCr coating was fabricated by HVOF spraying using a new type of WC-CoCr powder in which the CoCr exists in the form of a metallic compound. The CoCr powder constituent was prepared by induction melting and mechanical milling. It was then combined with a WC-Co composite nanopowder and the mixture was agglomerated by spray drying and heat treating. The powders and coatings produced were characterized by means of XRD, EDS, and BSE analysis, nanoindentation testing, and potentiodynamic polarization studies. The results show that the presence of the intermetallic CoCr compound makes nanostructured WC-CoCr coatings harder and much more corrosion resistant than conventional WC-Co-Cr coatings in which Cr exists as an unalloyed metal.

Plasma sprayed chromium oxides coatings have been widely applied in anilox rolls and pump seal for many years. This paper is researching the effect of nanostructured Cr 2 O 3 5SiO 2 3TiO 2 composite powder preparation when adding nano-size SiO 2 and TiO 2 powder in Cr 2 O 3 powder, to prepare for through spray drying, high temperature sintering and flame density. The microstructure of powder and plasma sprayed coating are analyzed by SEM and XRD, compared with pure Cr 2 O 3 powder and METCO 136F powder. The Microhardness of the coatings are measured by 402MVA TM Vickers hardness tester. Fracture test is used to analysis the ductility of coatings, and the fracture appearance is analyzed by SEM. The result indicates that the mechanical behaviors of nanostructured Cr 2 O 3 5SiO 2 3TiO 2 coating has better performance in the nature of hardness and ductility.

Chromium oxide coatings are used in gas turbine engines in anti-wear applications. Ultrafine YPSZ and WC/Co feedstock powders have already been widely used to prepare the ultrafine structured YPSZ and WC/Co coatings, which exhibited improved mechanical properties when compared to those of conventional coatings. Ultrafine chromium oxide powders, prepared by the method of solution precipitation, can not be directly used as plasma spray feedstock powder, because of its low mass of individual ultrafine particle and not good flowability. In this paper, spray drying and heat treatment are used to reprocess the ultrafine chromium oxide powder. The chromium oxide coating is prepared by plasma spraying. X-ray diffraction (XRD) is used to analyze the phase constituents of the feedstock powder and coatings. Scanning electron microscopy (SEM) is used to observe the morphology and particle size of ultrafine powder feedstock powder as well as to examine the microstructure of the chromium oxide coating. In addition, loose density and flowability of the feedstock powder and hardness and bond strength of the ultrafine chromium oxide coating are measured. Experimental results show that the large agglomerated ultrafine chromium oxide feedstock powder after being reprocessed are spherical, have good flowability and high loose density, which are suitable for plasma spraying. The wear properties and microstructure of the ultrafine chromium oxide coatings are improved when compared to the ones of the conventional coatings.

With the incoming of HVOF, the coating properties and application extent of WC-Co type have been greatly improved, in the recent years, we found that the characteristics of WC-Co powder has some influence on its coating properties prepared by HVOF. In this paper, study has been prepared on powders made from aboard and Beijing General Research Institute of Mining & Metallurgy properties such as fluidity, aspect, profile of coating SEM and carbon content, also phase structure and properties analysis of HVOF coating has been made. Finally, influence of powder preparing technology and HVOF technology parameters of different powders for coating properties have been described.

Novel Focused Ion Beam (FIB) voltage-contrast technique combined with TEM has been used in this study to identify a certain subtle defect mechanism that caused reliability stress failures of a new product. The suspected defect was first isolated to a unique via along the row through electrical testing and layout analysis. Static voltage contrast of FIB cross-section was used to confirm the suspected open defect at the via. Precision Transmission Electron Microscope (TEM) was then used to reveal the detail of the defect. Based on the result, proper process changes were implemented. The failure mode was successfully eliminated and the reliability of the product was greatly improved.

A single bit failure is the most common and the most difficult failure mode to analyze in a Static Random Access Memory (SRAM). As chip feature sizes decrease, the difficulties compound. Traditional failure analysis techniques are often ineffective, particularly for high temperature operating life (HTOL) failures, because HTOL failures are most often caused by subtle physical defects. A new analysis approach, using Focused Ion Beam (FIB) cross-sectioning combined with FIB passive voltage contrast (PVC), greatly enhances the analysis success rate. In this paper, we outline the use of these new techniques and apply them to a technologically important problem.