scholarly journals Fabrication of GaN nanowires containing n+-doped top layer by wet processes using electrodeless photo-assisted electrochemical etching and alkaline solution treatment

2021 ◽  
Author(s):  
Michihito Shimauchi ◽  
Kazuki Miwa ◽  
Masachika Toguchi ◽  
Taketomo SATO ◽  
Junichi Motohisa
Keyword(s):  
Alkaline Solution ◽  
Electrochemical Etching ◽  
Solution Treatment ◽  
Gan Nanowires

Formability of Hydroxyapatite on Beta-Type Ti-Nb-Ta-Zr Alloy for Biomedical Applications through Alkaline Treatment Process

2007 ◽  
Vol 352 ◽  
pp. 297-300
Author(s):  
Toshikazu Akahori ◽  
Mitsuo Niinomi ◽  
Masaaki Nakai
Keyword(s):  
Alkaline Solution ◽  
Biomedical Applications ◽  
Treatment Process ◽  
Solution Treatment ◽  
Sodium Titanate ◽  
Alkaline Treatment ◽  
Simple Method ◽  
Metallic Biomaterials ◽  
Naoh Solution ◽  
Bioactive Surface Modification

Titanium and its alloys have been widely used as biomaterials for hard tissue replacements because of their excellent mechanical properties and biocompatibility. However, the bonding between their surfaces and bone is not enough after implantation. The bioactive surface modification such as a hydroxyapatite (HAp) coating on their surfaces has been investigated. Recently, a simple method for forming HAp layer on the surfaces of titanium and its alloys has been developed. This method is called as alkaline treatment process. In this method, HAp deposits on the surfaces of titanium and its alloys by dipping into simulated body fluid (SBF) after an alkaline solution treatment that is followed by a baking treatment (alkaline treatment). This process is applicable to newly developed beta-type Ti-29Nb-13Ta-4.6Zr alloy (TNTZ) for biomedical applications achieving bioactive HAp modification. In this study, the morphology of the HAp layer formed on the surface of TNTZ was investigated after various alkaline treatments followed by dipping in SBF. The formability of HAp on the surface of TNTZ was then discussed. The formability of HAp on TNTZ is much lower than that of commercially pure Ti, Ti-6Al-4V ELI and Ti-15Mo-5Zr-3Al alloys, which are representative metallic biomaterials. The formability of HAp on TNTZ is improved by increasing the amount of Na in the sodium titanate gels formed during an alkaline solution treatment where the NaOH concentrations and the dipping time are over 5 M and 172.8 ks, respectively. The formability of HAp on TNTZ is considerably improved by dipping in a 5 M NaOH solution for 172.8 ks. This condition for alkaline solution treatment process is the most suitable for TNTZ.

A TEM microscopical investigation of the magnetic domain structure of a metastable austenitic stainless steel

1994 ◽  
Vol 52 ◽  
pp. 696-697
Author(s):  
G. Fourlaris ◽  
T. Gladman
Keyword(s):  
Tensile Strength ◽  
Stainless Steel ◽  
Austenitic Stainless Steel ◽  
Cold Rolling ◽  
Solution Treatment ◽  
Magnetic Domain ◽  
High Strength ◽  
Medium Carbon Steel ◽  
Magnetic Characteristics ◽  
Metastable Austenitic Stainless Steel

Stainless steels have widespread applications due to their good corrosion resistance, but for certain types of large naval constructions, other requirements are imposed such as high strength and toughness , and modified magnetic characteristics.The magnetic characteristics of a 302 type metastable austenitic stainless steel has been assessed after various cold rolling treatments designed to increase strength by strain inducement of martensite. A grade 817M40 low alloy medium carbon steel was used as a reference material.The metastable austenitic stainless steel after solution treatment possesses a fully austenitic microstructure. However its tensile strength , in the solution treated condition , is low.Cold rolling results in the strain induced transformation to α’- martensite in austenitic matrix and enhances the tensile strength. However , α’-martensite is ferromagnetic , and its introduction to an otherwise fully paramagnetic matrix alters the magnetic response of the material. An example of the mixed martensitic-retained austenitic microstructure obtained after the cold rolling experiment is provided in the SEM micrograph of Figure 1.

The Effect of Dry Mix Sodium Hydroxide onto Workability and Compressive Strength of Geopolymer Paste

2020 ◽  
Vol 12 (9) ◽  
Author(s):  
A. Z. Mohd Ali ◽  
◽  
N. A. Jalaluddin ◽  
N. Zulkiflee ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Fly Ash ◽  
Sodium Hydroxide ◽  
Sodium Silicate ◽  
Alkaline Solution ◽  
High Emission ◽  
New Material ◽  
Curing Regime ◽  
Solid Form ◽  
Geopolymer Paste

The production of ordinary Portland cement (OPC) consumes considerable amount of natural resources, energy and at the same time contribute in high emission of CO2 to the atmosphere. A new material replacing cement as binder called geopolymer is alkali-activated concrete which are made from fly ash, sodium silicate and sodium hydroxide (NaOH). The alkaline solution mixed with fly ash producing alternative binder to OPC binder in concrete named geopolymer paste. In the process, NaOH was fully dissolved in water and cooled to room temperature. This study aims to eliminate this process by using NaOH in solid form together with fly ash before sodium silicate liquid and water poured into the mixture. The amount of NaOH solids were based on 10M concentration. The workability test is in accordance to ASTM C230. Fifty cubic mm of the geopolymer paste were prepared which consists of fly ash to alkaline solution ratio of 1: 0.5 and the curing regime of 80℃ for 24 hours with 100% humidity were implemented. From laboratory test, the workability of dry method geopolymer paste were decreased. The compressive strength of the dry mix of NaOH showed 55% and the workability has dropped to 58.4%, it showed strength reduction compared to the wet mix method.

Influence of Solution Treatment, Sr-Modification and Short Fibre Reinforcement on the Eutectic Morphology of Al-Si Alloys

2006 ◽  
Vol 43 (10) ◽  
pp. 505-519 ◽  
Author(s):  
Fernando Adrián Lasagni ◽  
Hans Peter Degischer ◽  
Maria Papakyriacou
Keyword(s):  
Solution Treatment ◽  
Short Fibre ◽  
Fibre Reinforcement ◽  
Sr Modification ◽  
Eutectic Morphology

Chemical deposition of hard composite coatings Ni–Cu–P–Cr2O3

2020 ◽  
pp. 179-181
Author(s):  
A.A. Abrashov A.A. ◽  
E.G. Vinokurov ◽  
M.A. Egupova ◽  
V.D. Skopintsev
Keyword(s):  
Chromium Oxide ◽  
Alkaline Solution ◽  
Composite Coatings ◽  
Chemical Deposition ◽  
Alkaline Solutions ◽  
Functional Surface ◽  
Heat Treated ◽  
Weakly Acid Solution ◽  
Coating Composition ◽  
Weakly Acidic Solution

The technological (deposition rate, coating composition) and functional (surface roughness, microhardness) characteristics of chemical composite coatings Ni—Cu—P—Cr2O3 obtained from weakly acidic and slightly alkaline solutions are compared. It is shown that coatings deposited from slightly alkaline solution contain slightly less phosphorus and chromium oxide than coatings deposited from weakly acid solution (2...3 % wt. phosphorus and up to 3.4 % wt. chromium oxide), formed at higher rate (24...25 microns per 1 hour of deposition at temperature of 80 °C), are characte rized by lower roughness and increased microhardness. The Vickers microhardness at 0.05 N load of composite coatings obtained from slightly alkaline solution and heat-treated at 400 °C for 1 hour is 13.5...15.2 GPa, which is higher than values for coatings deposited made of weakly acidic solution. The maximum microhardness of coatings is achieved at concentration 20 g/l of Cr2O3 particles. The technology of chemical deposition of Ni—Cu—P—Cr2O3 coatings formed in slightly alkaline solution is promising for obtaining of materials with increased hardness and wear resistance.

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