Assembly Reliability and Molding Material Comparison of Miniature Integrated High Power Module with Insulated Metal Substrate

Given the increasing demand for power density and lightweight specifications, the discrete transistor outline-type package is no longer sufficient for personal vehicle. The new generation of high-power drive needs excellent heat dissipation and miniaturized system simultaneously. However, a traditional architecture of power module, direct bonding copper substrate, has serious warpage deformation and limitation of the heat dissipation. Therefore, a power module with an insulated metal substrate (IMS) is proposed. The proposed power module has a smaller volume, better electrical and thermal performance, and high reliability to be utilized in personal vehicles. A fine-quality assembly process is also presented and verified. Furthermore, two different kinds of molding materials that are widely used in power modules, silicone gel and epoxy, are utilized. The IMS-type module with silicone gel molding fails the temperature cycling test (TCT) with the delamination of the solder layer. The module with epoxy successfully passes the automotive-grade reliability tests, including TCT, highly accelerated stress test, high-temperature reverse bias, and intermittent operational life test according to the standard of AEC-Q101. The finite element analysis for the IMS power module is presented and analyzed under the condition of TCT to estimate the mechanical behavior of the solder layer. The equivalent plastic strain of solder layer with silicone gel and epoxy are 0.76 and 0.08 after TCT, separately. The main reason can be attributed to the coefficient of thermal expansion between the IMS and molding material. According to the analyzed results, the effect of molding material should not be ignored in the power modulus.

COMPARISON OF THE ADDITION OF Manihot utilisima (PATI UBI WOOD) TO DIMENSIONAL STABILITY OF IRREVERSIBLE HYDROCOLLOID MOLD

Alginate impression material is used to print the teeth and the oral tissues; alginate molding material is from abroad and expensive. Modification to the impression material alginate with cassava starch with 1: 1 obtained detailed reproduction of the same printed material alginate without added with cassava starch. The study's objective was to get an alternative form of printed material alginate plus Manihot utilisima (cassava starch) with the nature of the physical properties following the standard. The study methods used laboratory experiments. The materials used in this study were printed material alginate (Hydrogum fast setting), starch cassava starch cap dua kelinci, water, and tools calliper inside digital. There were four groups of a control group, a group cassava starch ratio of 50: 50, groups of cassava starch ratio of 60: 40, and a comparison group of cassava starch 70: 30. The results were dimensional stability of printed materials Alginate without additions were (73.72, 48.77, 30.51), the dimensional stability of the printed material alginate with a ratio of 50: 50 were (74.24, 40.82, 30.76), the dimensional stability of the printed material alginate with a ratio of 60: 30 were ( 75.39, 49.67, 31.57), and the results of dimensional stability alginate ((irrevesible hydrocolloid ) molding material with a ratio of 70: 30 were (76.36, 50.94, 32.86). The conclusion is the addition of Manihot utilisima on standard printed material alginate (irrevesible hydrocolloid) obtained dimensional stability test results that met the standards at a ratio of 50: 50 of ANSI/ADA no.18/1992. Manihot utilisima was one of the appropriate alternatives as a mixture in impression material alginate (irrevesible hydrocolloid).

High-density micro- and nanogranular ceramics. Transition of open pores to closed ones. Part 1. Preparation of powder, molding material, molding

An explanation of the processes that occur when producing high-density micro- and nanogranular ceramics without the use of external pressure is proposed on the basis of data accumulated in the literature. It is known that pore growth begins after the beginning of the transition of open pores to closed ones, which begins at about 30 % open porosity. It is necessary to maintain open pores to the maximum possible total density of sintered ceramics. This can be achieved by slowing down the formation of areas of local compaction (unequal density of samples) by various methods. Preservation of open pores is facilitated by such a decrease in the rate of shrinkage at which a self-consistent compaction of the local seals and the less dense zones surrounding them is realized. Such a regime can be implemented in different ways: by reducing the activity of powder particles (preliminary heat treatment of the powder, preliminary low-temperature sintering ― presintering), the use of additives that slow down shrinkage (obtaining transparent ceramics without external pressure), at the stages of preparing the molding material, molding blanks, removing the binder by adjusting the heating rate of the sample (sintering with an adjustable rate of shrinkage), prolonged sintering at a relatively low temperature in 2-stage sintering. This is part 1 of a series of 3 articles. Ref. 61.

Non-fire clay heat insulation from self-sealing masses based on burnable additives of plant origin. Part 1. The choice of burnable additives of plant origin for self-consolidation of masses in a hydraulically closed volume

It is proposed to modify the method of obtaining self-compacting masses by changing the nature of the compacting component ― from expensive and environmentally unsafe polystyrene to a burnable plantbased additive that can self-absorb shrinkage moisture from the molding material enclosed in a hydraulically closed volume. At the same time, part of the mixing water under pressure penetrates into the clay particles with pre-modified physicochemical properties of the surface, forming a semi-permeable shell. Ill. 3. Ref. 3.

The pottery traditions of Levshinskiy stage of the Kama Neolithic and Novoilyinskaya Eneolithic cultures

The following paper deals with the complexes of the late (Levshin) stage of the Kama culture and the early Eneolithic ceramic complexes of the Novoilyinskaya culture of the Middle Prikamye within the framework of a historical-cultural approach to the study of pottery. In the course of the work, the most stable traditions of raw material selection were highlighted: silty clay was used for the Kama culture; clay and silty clay were used in equal shares for the manufacture of Novoilyinskaya ceramics. For the manufacture of Kama ceramics raw materials were initially dried and crushed; this tradition was absent in the Novoilyinskaya culture. In both cultures mostly unsprayed (ductile) raw materials were used. As a result, it turned out that the population of the Kama region of the early Eneolithic was formed on the basis of the genesis of the local Neolithic population - the Kama culture representatives with the new (Volga) population. This fact may be indicated by differences in the skills of preparing plastic raw materials, mineral impurities for the preparation of the molding material, as well as the methods of applying the ornament.

REGULATING OF CAST CONSTRUCTIONS PROPERTIES BY INTENSIFYING HEAT EXCHANGE IN MOLD WITH GASIFIED PATTERN

The paper discusses ways to intensify the heat exchange of the casting in the mold of particulate filler. These methods include the supply of refrigerant to the mold, the dynamic and aerodynamic movement of the refractory filler around the casting. The examples of application of these methods to increase the local properties of cast iron cylinder block body are shown. Application of aerodynamic movement of molding material for aluminum castings has allowed to increase their mechanical properties in 1,3–1,6 times.