Preparation and Ignition Properties of Tantalum Nitride Thin-Film Energy Transducers

Tantalum nitride (TaN) has excellent electrical properties that can be used as an energy transducer in the ignition field. In this study, TaN film transducers with different bridge parameters were designed and fabricated in an attempt to reduce its energy consumption. The ignition sensitivity of the film transducers was tested using the Langley method. The results revealed that the ignition voltage is the lowest when the thickness of the film is 0.9 µm. If the thickness and length of the bridge film are fixed, the ignition voltage of the transducer first decreases and then increases with the width of the bridge film increases. When the thickness and width of the bridge film are fixed, the ignition voltage of the transducer is first decrease and then increase with the length of the bridge film increases. We also evaluated the ignition mechanism of TaN film transducers. By comparing the performance of TaN, semiconductor bridge (SCB), and nickel–chromium (Ni–Cr) film transducers, the TaN and SCB transducers are proven to have similar ignition performances, which are better than the Ni–Cr transducer. The negative temperature coefficient of TaN and the positive feedback after the initial electrothermal ignition promoted the growth and strengthening of plasma in the bridge film, allowing the medicament to ignite quickly. When the feasibility of the process and the influence of the bridge film parameters on ignition sensitivity are considered, the preferred design parameters of the transducer are a thickness of 0.9 µm and a bridge film size of 0.3 mm×0.3 mm. This study shows that TaN can be utilized as a high-performance transducer.

Electrodeposition of Thick and Crack-Free Fe-Cr-Ni Coatings from a Cr (III) Electrolyte

The electrodeposition of iron-nickel-chromium coatings is a more environmentally friendly and economical alternative to hard-chrome coatings made from chromium (VI) electrolytes and stainless-steel bulk materials. The aim of the study was to develop a suitable deposition method for thick and low-crack Fe-Cr-Ni coatings. Iron-nickel-chromium coatings were electrodeposited using a more ecological chromium (III) electrolyte with direct current (DC), stepped direct current, and pulse current (PC). The influence of the deposition method on the electrolyte aging, the alloy composition of the coating, and their microstructure was investigated. Corrosion studies of the Fe-Cr-Ni coatings in 3.5% NaCl solution were performed using polarization tests. Furthermore, hardness measurements and scratch tests were carried out to determine the adhesion strength. Phase analyses were performed by X-ray diffraction, and the chemical composition and microstructure were characterized by scanning electron microscopy. Using the stepped DC and PC method, crack-free Fe-Cr-Ni coatings were successfully deposited.

AUBERT & DUVAL CNS (35NiCr6)

Aubert and Duval CNS (35NiCr6) is a medium-carbon, nickel-chromium, direct hardening alloy steel. It is a medium hardenability steel in the 0.30 to 0.37 mean carbon content classification. This steel is frequently used for water-quenched parts of moderate section size and for oil-quenched parts of small section size. This datasheet provides information on composition, physical properties, hardness, elasticity, and tensile properties. It also includes information on casting. Filing Code: SA-878. Producer or source: Aubert & Duval S.A. (a member of the Eramet Group).

Shear Bond Strength of Repaired Ceramic-Metal Restorations Using Different Bonding Agents with Different Surface Treatments

Background: Fracture of ceramic-metal restorations is a major problem facing the dentists and the patients. There are several bonding systems currently available in the market to repair the fractured ceramic-metal restorations inside or outside the oral cavity. Purpose: The purpose of this study was to test the efficiency of repairing of metal-ceramic restorations using different bonding systems with different surface treatments. This efficiency was tested through the conduction of shear bond strength of the composite bonded to the porcelain and to nickel-chromium alloy using three different bonding agents (Excite, AdheSE, and Prompt L-Pop) with four different surface treatments (sandblasting and enchant, diamond stone roughening, sandblasting and hydrofluoric acid etching, or without surface treatment). Materials and Methods: A total of 120 specimens were prepared, 60 specimens from porcelain and 60 specimens from nickel-chromium alloy. Each group was divided into three equal subgroups, 20 specimens each, corresponding to the 3 bonding agents used. Each subgroup was further subdivided into four subgroups, 5 specimens each, corresponding to the surface treatment procedures. Bonding agents applied over all specimens and cured, followed by application of a micro-hybrid light-cured composite resin (Tetric Ceram). Thermal cycling was done for all specimens between 5°C and 55°C for 1000 cycles with a 10-second dwell time. Shear bond strength test was conducted using a universal testing machine ata cross-head speed of 0.5 mm/min. Results: The highest shear bond strength value recorded for the porcelain specimens bonded with Excite bonding agent with surface treatment sandblasting and hydrofluoric acid etching. In metal groups, the AdheSE bonding agent showed the highest shear bond strength value with the same surface treatment of the porcelain specimens. It was observed that sandblasting followed by hydrofluoric acid etching produced the most effective treatment method for porcelain and metal surfaces. Conclusion: The most effective technique for repairing metal ceramic restoration was sandblasting with hydrofluoric acid etching as surface treatment together with AdheSE or Excite bonding agents.

Evaluation of Surface Roughness of a Ni-Cr Alloy Treated With the Nd/YAG Laser and the Sandblast Technique

Introduction: This study was to assess the effect of various output parameters of laser treatment on roughening the surface of a commercial nickel-chromium (Ni-Cr) alloy as compared to the sandblasting technique. Materials and Methods: Ninety-six disk-shaped (5 mm diameter and 2 mm thickness) specimens in total were made of a nickel-chromium alloy by using the lost-wax technique. Air-abrasion surface treatment was used for sixteen specimens. Specimens were divided into six groups; one of them was sandblasted and the rest were irradiated by different Nd:YAG laser output parameters as follows: Group A: energy: 122 mJ, frequency: 20 Hz, irradiation duration: 20 seconds, spot size: 1.5 mm; Group B: energy: 122 mJ, frequency: 20 Hz, irradiation duration: 20 seconds, spot size: 3.5 mm; Group C: energy: 122 mJ, frequency: 10 Hz, irradiation duration: 20 seconds, spot size: 3.5 mm; Group D: energy: 102 mJ, frequency: 10 Hz, irradiation duration: 20 seconds, spot size: 3 mm; Group E: energy: 102 mJ, frequency: 20 Hz, irradiation duration: 20 seconds, spot size: 3 mm. The surface roughness of all surface-treated specimens was evaluated by using a profilometer, and their average roughness (Ra) was calculated. The average value of each group was analyzed by t test and one-way ANOVA (SPSS 17). Results: Significant differences (P<0.05) were observed between the study groups. The highest Ra was achieved for the sandblasted group. The Ra value in group C was the highest value among the laser-etched groups. Conclusion: Based on the results, Nd:YAG laser irradiation increases surface roughness, but it is not as efficient as the sandblasting method as a gold standard.

STUDY ON THE EFFECT OF COMPOSITION AND VARIATION OF Sn/Zn COOLING MEDIA ON NICKEL ALLOY STEEL THROUGH HOT FORGING AND AUSTEMPERING

STUDY ON THE EFFECT OF COMPOSITION AND VARIATION OF Sn/Zn COOLING MEDIA ON NICKEL ALLOY STEEL THROUGH HOT FORGING AND AUSTEMPERING. Laterite steel with nickel content is expected to be a solution to overcome the lack of domestic steel availability and dependence on imports. This research was conducted to develop Nickel-Chromium-Molybdenum alloy steel used Grinding ball for cement industrial applications. Grinding ball is the one of imported steel products needed to be crushing and size reduction the ores or cement. In addition to import issues, grinding balls have a significant problem: their mechanical properties that do not meet SNI 1049 require the material to have a minimum hardness value of 45 HRC. In this study, the characteristics of Nickel alloy steel were investigated further through heat treatment of forgings heated at the austenitizing temperature of 950 °C and austempering with variations in the cooling medium of Sn/Zn solution. The cooling medium was chosen because it has a melting temperature in the phase diagram area to form the bainite microstructure with complex and challenging characteristics, both of which are required in material for grinding ball applications. In particular, the hardness value that passed the SNI 1069 standard was the use of samples with a Cr-Mo alloy of 1%-wt with a hardness value of 45.92 HRC for Sn Austemper and 48.07 HRC for Zn austemper.

Analysis on the Properties of NC30Fe alloy for U-bend tubes of Steam generator

The Nickel-Chromium-Iron Alloy (NC30Fe), which is an austenitic nickel-based alloy as the ideal material for U-bend tubes of steam generator in PWR nuclear power plant because of its good strength and corrosion-resistant and used widely in domestic and abroad. The manufacturing requirements of NC30Fe alloy of steam generator U-bend tubes for Hua-long Pressurized Reactor (HPR1000) and Advanced Passive PWR (AP1000) were compared and the heat treatment process, chemical composition, mechanical properties, metallographic structure were analyzed and studied.