Polymethyl Methacrylate Binder Removal from an Alumina Compact: Microwave Versus Conventional Heating

1992 ◽  
Vol 269 ◽  
Author(s):  
Edmund H. Moore ◽  
David E. Clark ◽  
Ronald Hutcheon

ABSTRACTCompact samples of alumina and polymethyl methacrylate have been heated in a 2.45 GHz microwave cavity and by conventional heating in an electric furnace. Various heating schedules have been used to effect the removal of the polymeric binder by thermal decomposition. Dielectric properties, porosity and other physical properties have been investigated in order to better understand the binder removal process in a microwave field. Results of the study emphasize the amount of carbon residuals remaining in the bulk.

Alloy Digest ◽  
1975 ◽  
Vol 24 (1) ◽  

Abstract BLACK DIAMOND STANDARD is an electric-furnace-melted, water-hardening carbon tool steel with an excellent reputation for use as the standard in general shop tools requiring extreme toughness and resistance to shock and impact. In the lower carbon ranges (0.50-0.70% carbon), it is used primarily for tools such as pins, punches, hammers and sledges. Black Diamond may be expected to give uniform and consistent results, although no definite limits of case depth or grain size are regularly guaranteed. This datasheet provides information on composition, physical properties, hardness, and elasticity. It also includes information on forming, heat treating, machining, joining, and surface treatment. Filing Code: TS-281. Producer or source: Crucible Specialty Metals Division, Colt Industries.


2020 ◽  
Vol 384 ◽  
pp. 121227 ◽  
Author(s):  
Kangqiang Li ◽  
Jin Chen ◽  
Jinhui Peng ◽  
Roger Ruan ◽  
Mamdouh Omran ◽  
...  

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 438
Author(s):  
Shuwei Yang ◽  
Bingliang Liang ◽  
Changhong Liu ◽  
Jin Liu ◽  
Caisheng Fang ◽  
...  

The (1–x)Ca0.61La0.26TiO3-xNd(Mg0.5Ti0.5)O3 [(1–x)CLT-xNMT, x = 0.35~0.60] ceramics were prepared via microwave sintering. The effects of sintering temperature and composition on the phase formation, microstructure, and microwave dielectric properties were investigated. The results show that the microwave sintering process requires a lower sintering temperature and shorter sintering time of (1–x)CLT-xNMT ceramics than conventional heating methods. All of the (1–x)CLT-xNMT ceramics possess a single perovskite structure. With the increase of x, the dielectric constant (ε) shows a downward trend; the quality factor (Qf) drops first and then rises significantly; the resonance frequency temperature coefficient (τf) keeps decreasing. With excellent microwave dielectric properties (ε = 51.3, Qf = 13,852 GHz, τf = −1.9 × 10−6/°C), the 0.65CLT-0.35NMT ceramic can be applied to the field of mobile communications.


2020 ◽  
Vol 31 (13) ◽  
pp. 10649-10656
Author(s):  
Hamza Nasir ◽  
Nasir Rahman ◽  
Zulfiqar ◽  
Tahirzeb Khan ◽  
Shahid Ali ◽  
...  

2016 ◽  
Vol 675-676 ◽  
pp. 635-638
Author(s):  
Jukkrit Kongphimai ◽  
Hassakorn Wattanasarn ◽  
Tosawat Seetawan

[(K0.5Na0.5 )0.935Li0.065]NbO3–Mn ceramics (Mn = 0, 1.50 and 3 mol %) (KNNL–Mn) were synthesized and measured dielectric properties. Which the K2CO3, Na2CO3, Li2CO3, Nb2O5 and MnO2 (0, 1.5, 3 mol%) were mixed by ball milling method and calcined powders at 1,073 K for 4 h and the sintered at 1,343 K for 2 h in air. The crystal structure was analyzed by XRD technique, the crystallite size was identified by Scherrer’s equation and calculated the theoretical density. It was found that, the XRD patterns of the KNNL–Mn ceramics added with Mn contents was indicated the tetragonal structure and. the crystallite size of Mn = 0, 1.50 and 3 mol% about 32 nm, 34 nm and 57 nm, respectively. The physical properties of the KNNL–Mn ceramics was found that the maximum theoretical density of 90.79 % for Mn = 1.50 mol%. The dielectric constant was found to be maximum of 909.77 and dielectric loss of 0.48 for Mn = 3 mol%.


Author(s):  
L.A. Morozova ◽  
S.V. Savel’ev

For the first time, an ultra-high-sensitivity method for measuring radio-thermal radiation was developed and used in practice in order to establish the difference in the physical properties of aqueous solutions of substances in the millimeter region of the spectrum. The method is used to study the dynamics of the dielectric properties of aqueous solutions depending on the composition of the base substance and its concentration. The dynamics of dielectric properties establishes a one-to-one correspondence between the number and concentration of ions of the dissolved basic substance contained in water and the number of water molecules involved in cooperative interaction, which gives a consistent microscopic picture of ion-water cooperative interactions in the studied aqueous solutions of K2SO4 and Cs2SO4. The density of water molecules perturbed by the ions of the base substance contained in the hydration shell at normal concentrations is proportional to the number of ions, while the transition to weaker solutions leads to the creation of multilayer hydration shells. This means that the number of perturbed water molecules, depending on the number of ions, increases according to a law different from linear. In accordance with the experimental data, the values of the absorption coefficients of aqueous solutions were determined in a wide range of concentrations for alkali metal sulfates. It is noted that alkali metal sulfates have physical properties that generalize the dynamics of dielectric constants depending on the concentration of the base substance. A monotonic increase in the values of the absorption coefficients of solutions with a decrease in the concentration of basic substances in the region of high dilutions was established with individual dynamics for each basic substance, reflecting the total hydration changes in salt solutions. Research has shown that the proposed method for measuring radio-thermal radiation fixes a significant difference in the values of the dielectric constants of aqueous solutions at high dilutions from their values for water.


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