جستجوی مقالات مرتبط با کلیدواژه « Silicone » در نشریات گروه « فنی و مهندسی »

Harsh and changing temperature conditions have detrimental effects on the coating of the body of a spacecraft. Thermal control paints are used to protect surface of a spacecraft against these damages. In this study a two-component silicone resin and different quantities of carbon black were used to make black thermal control paint. These coatings were applied to aluminum substrates with different surface preparations including anodic treatment, abrasive treatment and solvent cleaning. To improve the paint adhesion, 3-aminopropeltriethoxysilane, wp-1 wash primer and DW1200 primer were used. The design of experiments was down with Taguchi method. The abrasion, adhesion, impact and bending tests were carried out on prepared paints. The results indicated that the coating made by RT604 resin, 3 percentage of pigment and DW1200 primer had the best abrasion and adhesion properties. Impact test and bending test of the paints showed high flexibility and impact resistance.

Magnesium alloys as biodegradable implants have attracted substantial attention since there’s no need to extract them & thus lowering patient’s pains and costs. But their high corrosion rate, makes it inevitable to coat them. In the present research, silicone doped calcium phosphate coating was successfully generated on AZ31 magnesium alloy via pulse electrodeposition, which made it possible to create nano structure morphology. XRD patterns indicated that primary coating was mainly consisted of DCPD, but after immersion in hot NaOH solution, pirmaryDCPD transformed into hydroxyapatite. FESEM images showed sponge-like structure consisting of nano blade crystals. EDS analysis proved the presence of silicone in the hydroxyapatite structure. According to EDS results, Ca/(P+Si) ratio would be equal to 2.35 which by considering the accelerating voltage, formation of siliconedoped hydroxyapatite is approved. Finally, polarization tests in ringer’s solution revealed that silicone-doped hydroxyapatite have greatly reduced corrosion rate. Corrosion rate was reduced from 121.06 μA/cm2 for bare metal, to 4.38 μA/cm2 for sample with silicone-doped hydroxyapatite coating.

In this investigation has been developed an innovation method for production of A356 metal foam with high strength without usage to the reinforcement particles. Silicone rubber mixed with dolomite powder in order to increasing of thermal resistance. In this paper manufacturing process parameters such as size and percent of Silicon-Dolomite granules, pouring temperature, and cooling rate were measured and evaluated. Results show the 750oC temperature, 50 vol. % Silicon granule, and granules with 5 mm diameter are best production parameters. Comparison of pressure test results between this foam and others reinforced foam with SiC and TiB2 particles, shows that present foams have 8-12 more times plateau stress and approximately a reduction 1/4 in the densification strain.