จำนวน Repository ( 3 )
การพัฒนาผลิตภัณฑ์เครื่องมือตัดปาดผิวโลหะนาโนเมตรจากโลหะผงทังสเตนคาร์ไบด์ที่ผลิตภายในประเทศ
The tungsten carbide powder which recycled from the scarps of cemented tungsten carbide produces the purity of 99%. Using this tungsten carbide powder to manufacture a cutting tool and test its properties are the main objective of this work. Based on the standard SNMG 120408 the cutting tool with the dimension of 12.7x12.7x4.76 is fabricated. With the 100 hours of Ball milling grinding Cobalt mixing and sintering at 1430 °C the experimental result is impressive. At 15% of mixedcobalt the cutting tool with the hardness of 2031.6 HV be able to cut S45C steel in the feed rate of 0.2 meters per revolution and 45 m/min in the cutting speed. Besides that it provides the depth of cut of 0.25 mm and when it reaches the cutting distance of 4200 mm the surface roughness is 3.65 μm. In comparison with the cutting tool made of imported tungsten carbide powder which has a hardness of 1254 HV it turned out that our cutting tool has the equivalent quality in terms of hardness and wear resistance. Hence this work is considered to be a material development and a tungsten carbide cutting tool manufacture those would be the vital base to lead us to a commercial production.
การเตรียมและศึกษาสมบัติทางโครงสร้างและแม่เหล็กของอนุภาคคอมโพสิตระดับนาโนเมตรของไฮดรอกซีอะพาไทต์และซิงก์เฟอไรท์ เพื่อประยุกต์ใช้ในการรักษามะเร็งในอนาคต
A promising composite of zinc ferrite (ZnFe2O4) and bioactive hydroxyapatite (Ca10(PO4)6(OH)2 ;HAp) has expected to potential for future bone reinforcing formation. In present study zinc ferrite and hydroxyapatite composite was prepared by solid state reaction route for easier control of structural and magnetic characteristics and with low cost. Hydroxyapatite powder was synthesized by precipitation method from chicken eggshell. Mixed powders with varying ZnFe2O4/HAp weight ratios from 2-10 wt% were milled together and uniaxially pressed and then sintered at 1200 oC for 3 hours. The XRD results showing no other phases of composite with only HAp and ZnFe2O4 phases were identified indicating high stability of HAp property. Phase fractions of ZnFe2O4 were found to increase from 10.8 to 18.73 wt% with increasing content of ZnFe2O4. FT-IR results of ZnFe2O4/HAp composite were only revealed vibration bands of standard HAp phase. This may due to the overlapping of the ZnFe2O4 vibrational bands with HAp bands. However their intense variations observed in HAp vibrational bands indicated the interaction between ZnFe2O4 and HAp. The surface morphology of these ZnFe2O4/HAp composite exhibited primary grain in nano scale with enhanced pore structure and Interconnectivity when ZnFe2O4 weight ratios increased; indicating high surface area for cell attachment and better good cell growth and differentiation. The higher saturation magnetization as well as higher super paramagnetic behavior could be easily altered by increasing ZnFe2O4 content in the composite.
พัฒนาวัสดุผงทังสเตนคาร์ไบด์ขนาดนาโนเมตรจากวัสดุรีไซเคิลชนิดซีเมนต์ทังสเตนคาร์ไบด์
WC powder was obtained from recycling cemented carbide scraps. This metal power contained tungsten carbide (WC) at 89.17% titanium (Ti) at 4.90% tantalum (Ta) at 3.56% niobium (Nb) at 1.31% and molybdenum (Mo) at 0.93%. Its particle size and distribution was in the range of 0.03-85.31 µm. After quality improvement of the metal powder by ball milling screening and separating the compounds the result showed that the particle size of the metal powder was decreased to 0.01-0.10 µm (10-100 nm). The average size of the powdered particle was 28 nm. The tungsten powder was in more perfect condition by 95.85%