Effect of Sealing Treatment of Modified Aluminum Phosphate Sealing Agent on Corrosion Resistance of Fe-Based Amorphous Coating

A modified aluminum phosphate sealing agent was prepared by using aluminum dihydrogen phosphate and silica sol as raw materials, and was used for sealing treatment of iron-based amorphous coating. The phase of sealing agent was analyzed by XRD. SEM and TG-DSC were used to characterize the surface morphology of the coating before and after sealing and the heat resistance of the sealing agent. The corrosion resistance of the sealing coating was evaluated by electrochemical measurements. The results show that the modified aluminum phosphate sealing agent has good heat resistance, and fine and close sealing layer was obtained, thus the corrosion resistance is significantly improved.

State-of-the-Art Review on Experimental Investigations of Textile-Reinforced Concrete Exposed to High Temperatures

Textile-reinforced concrete (TRC) is a promising composite material with enormous potential in structural applications because it offers the possibility to construct slender, lightweight, and robust elements. However, despite the good heat resistance of the inorganic matrices and the well-established knowledge on the high-temperature performance of the commonly used fibrous reinforcements, their application in TRC elements with very small thicknesses makes their effectiveness against thermal loads questionable. This paper presents a state-of-the-art review on the thermomechanical behavior of TRC, focusing on its mechanical performance both during and after exposure to high temperatures. The available knowledge from experimental investigations where TRC has been tested in thermomechanical conditions as a standalone material is compiled, and the results are compared. This comparative study identifies the key parameters that determine the mechanical response of TRC to increased temperatures, being the surface treatment of the textiles and the combination of thermal and mechanical loads. It is concluded that the uncoated carbon fibers are the most promising solution for a fire-safe TRC application. However, the knowledge gaps are still large, mainly due to the inconsistency of the testing methods and the stochastic behavior of phenomena related to heat treatment (such as spalling).

Effect of Boronizing Treatment on the Conductivity of a High-Conductivity and Heat-Resisting Al-Zr Alloy Conductor Material

The effect of boronizing treatment on the conductivity of a high-conductivity and heat-resistant Al-Zr alloy conductor material was studied. The results showed that the conductivity of industrial pure Al containing transition element (Ti, V, Cr, Mn)>0.01 wt % (mass fraction, the same below) was improved to a certain extent by using boronizing treatment to remove transition metal elements through the formation of borides. Using the boronizing treatment, B can react with transition elements to form blocky (Ti, V, Fe)B2 and flocculent (Ti, V, Fe, Zr)B2. The boronizing treatment makes Ti and V out of the solid solution state, form borides and finally deposit to the bottom of the furnace, thus significantly improving the conductivity of the ingot. In addition, Cr and Mn were not found in the borides at the bottom of the furnace. However, for the high-conductivity and heat-resisting Al-Zr alloy conductor material, B will have poison effects on Zr during boronizing treatment, thus reducing the heat-resistance of the alloy. Therefore, in the preparation process of high-conductivity and heat-resistant Al-Zr alloy conductor material, the converter process should be added after boronizing treatment to ensure that the Al-Zr alloy conductor material has good heat-resistance and conductivity at the same time.

Utilization of bus tree wood (Melaleuca sp) as environmentally friendly fuel for household industrial scale Aluminum smelting stoves in Merauke, Papua

The purpose of this study is the use of bus wood trees as fuel for aluminum smelting for the home industry because it has a good heating value and is very efficient, from the laboratory test results, the bus tree wood has a calorific value of 5981 (calories/g). The methods used experimental and analytical to get the results from the use of bus wood as fuel for aluminum smelting which will certainly produce good mechanical properties. The results obtained a good combustion process that releasing all the heat contained in a fuel and done with three combustion control processes, including a fairly high temperature to ignite and maintain the flame of the fuel, turbulence or mixing O2 and the use of good fuel and sufficient time to complete combustion process. The fuel (bus wood) which is inputted in the furnace is designed so that the combustion process takes place more completely with minimal heat losses. The results of temperature changes seem a thermocouple and crucible furnace insulator material were very good heat resistance hence the time of the melting process it doesn't take longer which is 15 minutes. The aluminum in crucibles has melted at a temperature of 723℃.

Silicone Resin-Based Intumescent Paints

Silicone resins are widely applied as coating materials due to their unique properties, especially those related to very good heat resistance. The most important effect on the long-term heat resistance of the coating is connected with the type of resin. Moreover, this structure is stabilized by a chemical reaction between the hydroxyl groups from the organoclay and the silicone resin. The novel trends in application of silicone resins in intumescent paints used mostly for protection of steel structures against fire will be presented based on literature review. Some examples of innovative applications for fire protection of other materials will be also presented. The effect of silicone resin structure and the type of filler used in these paints on the properties of the char formed during the thermal decomposition of the intumescent paint will be discussed in detail. The most frequently used additives are expanded graphite and organoclay. It has been demonstrated that silicate platelets are intercalated in the silicone matrix, significantly increasing its mechanical strength and resulting in high protection against fire.

Preparation and Properties of One Component RTV Silicone Resin Composed of Polysiloxane Block Copolymer

One component room temperature vulcanized (RTV) silicone resin was prepared by combination of a kind of D-T polysiloxane block copolymer with crosslinker and catalyst. Transparent coating with good elastoplasticity without any inorganic filler could be obtained by exposing the RTV silicone to air at room temperature. The structure of D-T block copolymer played an important role in the properties of the cured products. It was synthesized by polycondensation of partially hydrolyzed phenyltrimethoxysilane (phenylsilsesquioxane, T units) with silanol end-capped polydimethylsiloxane (PDMS, D units). The effects of the viscosity of phenylsilsesquioxane and the D/T ratio on the properties of cured product were investigated. When phenylsilsesquioxane (10000cP at 80°C) was used and the D/T ratio was 2.0~2.3, cured products with tensile strength above 2.5MPa and elongation above 70% were prepared. RTV silicone resin composed of such kind of D-T block copolymer had good heat resistance because the existence of phenyl group and the highly cross-linked 3D structure. The Tonset was 387.6°C and the Tmax was 518°C.

Quartz fiber cloth-reinforced semi-aromatic thermosetting polyimide composite with high-frequency low dielectric constant

We report a series of semi-aromatic thermosetting polyimide (PI) resins that can be used as matrix for copper-clad laminates for high-frequency applications. The poly(amic ester) (PAE) resins derived from the diester of 1,2,4,5-cyclohexanetetracarboxylic dianhydride, aromatic diamines (the mixture of 2,2′-dimethylbenzidine and 2,2′-bis[4-(4-aminophenoxy) phenyl] propane), and the monoester of nadic anhydride were synthesized by Polymerization of Monomer Reactants (PMR) method. The structure conversion of PAE resins at different temperatures was investigated and the B-stage PI powders prepared by thermally baking the PAE resins at 220°C are nearly fully imidized. The viscosities of the B-stage PI powders and the mechanical and thermal properties of the cured PI resins were optimized by varying the molar ratio of the two diamines. The cured PI resins possess low and steady dielectric constants ( Dk) below 3.0 and dielectric dissipation factors ( Df) of less than 0.01 at high frequency of 1–12 GHz. Furthermore, the quartz fiber cloth-reinforced semi-aromatic thermosetting PI composites (QF/PI) exhibit excellent dielectric performance, good heat resistance, and mechanical properties. At a high frequency of 1–12 GHz, the Dk of QF/PI-4 is stable in the range of 3.16–3.2, and the Df is stable in the range of 0.0026–0.0046. These results suggest the potential of the semi-aromatic QF/PI for use in high-frequency IC boards.

Thermal, Mechanical, and Microstructural Study of PBO Fiber during Carbonization

Poly(p-phenylene benzobisoxazole) (PBO) fiber shows fascinating properties including excellent mechanical performance, high crystallinity, and fairly good heat resistance as a kind of polymer fiber. Its properties make it a possible candidate as a precursor of carbon fiber. This paper mainly investigates the possibility of yielding carbon fiber from PBO by direct carbonization using a continuous process and multiple properties of yielded fiber treated under different heat treatment temperature (HTT). The results show that PBO fiber was able to sustain an HTT as high as 1400 °C under the inert atmosphere and that the shape of fiber was still preserved without failure. Using thermal gravimetric analysis (TGA) and TGA coupled with mass spectroscopy (TGA-MS), it was found that a significant mass loss procedure happened around 723.3 °C, along with the emission of various small molecules. The mechanical performance first suffered a decrease due to the rupture of the PBO structure and then slightly increased because of the generating of graphite crystallite based on the broken structure of PBO. It was observed that PBO’s microstructure transformed gradually to that of carbonaceous material, which could be the reason why the change of mechanical performance happened.

Structures and Properties of Self - crosslinking Silicone Resin

Highly transparent silicone resin with self-crosslinking structure was prepared using phenyltrimethoxysilane, diphenyldimethoxysilane, 1,3,5,7-cyclotetra(methyl siloxane) and bisvinyltetramethyldisiloxane as main raw materials. The structure of silicone resin was determined by Fourier Transform Infrared Spectroscopy (FT-IR). The light transmittance was measured by UV-Vis spectroscopy. Thermogravimetric analysis (TGA) was used to study the thermal decomposition process. The microstructure of cured self-crosslinking silicone resin is more uniform, resulting in better light transmittance up to 100% in the range of 400nm ~ 800nm. The cured has relatively good heat resistance, the initial thermal decomposition temperature of the cured could be up to 315.8 °C. SEM observations show that the self-crosslinking silicone has a uniform, textured structure, higher transparency compared with the existing condensation silicone material, and can be used as advanced architectural translucent materials and optics packaging materials.

ANALISIS PROSES PENGECORAN DAN PERMESINAN BUSHING RODA KERETA DI GALANGAN KAPAL

This study aims to know the process of making brass bushing to succeed into a product along with the value of violence and roughness. Methods used include evaporative method, CO2 sand mold and method x. This research is done by first preparing tools and materials then done casting process where brass used in melted then cast into casting castings and in chill with well water. Furthermore, the machining process using a lathe with carbide chisel and engine rotation used for 590 RPM. From roughness test result after machining process got value at outside diameter of point A 2,532 μm, point B equal to 2,544 μm, point C equal to 2,673 μm, then diameter in point A equal to 1,539 μm, point B equal to 1,749 μm. For the value of hardness on the method of sand mold CO2 obtained an average value of 42 HRB, evaporative methods of 33.2 HRB and method x obtained an average value of 39.8 HRB. Fromithese results it is known that the hardness of the best bushing in this research is by the method of sand mold CO2 because it has good heat resistance and good mold density.