This paper investigates the effects of thin plastically deformable layers embedded in an elastic coating upon debonding of a multilayer from its substrate. Such coatings are normally deposited at high temperature and cooled to ambient, resulting in significant stresses from thermal expansion mismatch. Other stresses can develop during subsequent thermal cycling if volumetric changes such as pha...

Functionally graded NiCoCrAlY/yttria-stabilized zirconia coatings were fabricated by plasma spraying using mechanically alloyed, plasma-spheroidized NiCoCrAlY/yttria-stabilized zirconia (YSZ) composite powders. Scanning electron microscopy (SEM) and energy dispersive X-ray spectrometry (EDS) analysis revealed that oxidation of aluminum, chromium and yttrium in the NiCoCrAlY alloy occurred in th...

Thermal sprayed coatings have wide engineering applications. There now exists a wide range of destructive and nondestructive testing (NDT) methods for surface coating inspections. This paper describes an application of Electronic Speckle Pattern Shearing Interferometry (ESPSI) for NDT of thermal sprayed surface coatings. In contrast to other conventional methods such as eddy current, ultrasonic...

The upconversion luminescence UCL of the hexagonal -phase NaYF4:Yb,Er nanophosphors as a function of temperature 300–450 K was examined under 978 nm light excitation. The thermal sensitivity was evaluated based on the UCL intensity ratio between H11/2– I15/2 and S3/2– I15/2 transitions RHS . Excitation power, particle sizes 37, 65, and 140 nm , ion doping concentrations, and with and without si...

Modern high power electronics devices consists of a large amount of integrated circuits for switching and supply applications. Beside the benefits, the technology exhibits the problem of an ever increasing power density. Nowadays, heat sinks that are directly mounted on a device, are used to reduce the on-chip temperature and dissipate the thermal energy to the environment. This paper presents ...

During the process of thermal spray coating, molten powders are sprayed and deposited on substrates to generate protective coatings. It is essential to have a clear understanding of the physics of droplet impingement on the surface of substrates for better control of the generation of splats and the structure of coating. A numerical model is developed in this paper to simulate the dynamics of t...

The performance of a fire resistant coating for tunnel passive fire protection under successive severe thermal loading is presented. The material falls under the class of potassium based geopolymers (K-geopolymer) and was prepared by mixing ferronickel (FeNi) slag, doped with pure alumina, with a highly alkaline potassium hydroxide aqueous phase. Its performance was assessed by subjecting a con...

The creation of a suitable inorganic colloidal nanocrystal ink for use in a scalable coating process is a key step in the development of low-cost thin film solar cells. We have developed an innovative method of using copper indium gallium disulfide (CIGS) nanocrystals as the building block for the fabrication of bulk CIGSSe thin films. The CIGS nanocrystal ink solution is applied directly on va...

Organic field-effect transistors (OFETs) were fabricated by depositing a regioregular poly(3-hexylthiophene) (P3HT) active layer using a dip-coating method. The field-effect mobility in OFETs depends on chain orientation and crystallinity and is related to direction and withdrawal speed with respect to the source/drain orientation. In this paper, how to control the structural and transport prop...