The increasing demand on high quality optical systems with complex geometries, low tolerances and a low installation space necessitates new replicative production systems for complex optical glass elements. The technology precision blank moulding shows promising properties to comply with these demands on an industrial bulk production. Due to the required high surface quality and low surface rou...

the kinetic of the heterogeneous chemical reaction of aluminum hydroxide and fluosilicic acid was studied. it was found that the diffusion of the reactants through the porous silica coating to the aluminum hydroxide surface and the interfacial chemical reaction between the diffusing reactant and aluminum hydroxide platelets control the overall reaction rate. these two phenomena were studied and...

Yttrium silicate coating[5, 6] is a promising candidate for oxidation resistant coating for its low oxygen diffusion coefficient and similar thermal expansion coefficient with silicon carbide. Webster et. al.[7] had prepared yttrium silicate coating on C/SiC using Y2O3/SiO2 slips by slip casting and sintering. The selected sintering parameters were 3 h at 1600 °C in flowing argon. The coating c...

In the present research, to form niobium carbide coating on the surface of AISI L2 steel Thermo-Reactive Deposition method (TRD) in a molten bath was used. Niobium carbide coating treatment was carried out at 1173 K, 1273 K, and 1373 K for 2, 4, and 8 hours. The molten bath contained 20wt.% borax (Na2B4O7), 5 wt.% boric acid (B2O3), and 75 wt.% ferro-niobium. The presence and properties of...

MCrAlY coatings are deposited onto superalloys to provide oxidation and corrosion protection at high temperature by the formation of a thermally grown oxide scale. In this project, the oxidation behaviour of a HVOF CoNiCrAlYSi coating on IN792 was studied for both isothermal oxidation (900, 1000 and 1100 °C) and thermal cycling (100-1100 °C). The microstructural evolution of the CoNiCrAlYSi coa...

In the present study, Thermo-Reactive Deposition method (TRD) in a molten bath was used to form niobium carbide coating on AISI L2 steel. The coating was formed in five different composition of borax (Na2B4O7), boric acid (B2O3), and ferro-niobium. For all of the five compositions of molten bath, niobium carbide coating treatment was carried out at 1173 K, 1273 K, and 1373 K for 2, 4 and 8 hour...

Titanium trialuminide coating on L10-type titanium aluminide alloys represents a valuable mean to improve oxidation resistance. Selection of L12-type titanium trialuminide alloys containing Mn as a coating material is particularly attractive because of its good ductility at room temperature and good oxidation resistance at high temperature of 1273 K. However, stability of the coated titanium tr...

Drug-eluting stents (DES) are commonly used in coronary angioplasty procedures. A DES elutes drug compounds from a thin polymeric coating into the surrounding coronary artery tissue to reduce in-stent restenosis (a significant lumen loss due to growth of vascular tissue). Biodurable (non-erodible) polymers are often used in the current DES coatings, which stay permanently in the patients. While...