ANNEALING BEHAVIOR OF Ni-TiO2 NANOCOMPOSITES

2019 ◽  
Vol 26 (10) ◽  
pp. 1950069 ◽  
Author(s):  
TE NIU ◽  
WEIWEI CHEN ◽  
HUANWU CHEN ◽  
LU WANG
Keyword(s):  
Composite Coatings ◽  
Strengthening Effect ◽  
Annealing Behavior ◽  
Heat Treated ◽  
Adhesion Wear ◽  
Before And After ◽  
Columnar Grains ◽  
Oxidation Layers ◽  
Equiaxed Grains ◽  
Worn Surface

Ni-TiO2 nanocomposite have been prepared by electrodeposition. The microstructure and tribological behavior of Ni-TiO2 nanocomposite before and after annealing have been investigated compared with as-deposited Ni-TiO2 composite. The results demonstrated that TiO2 nanoparticles usually collected along the grain boundaries and nickel grains changed from columnar grains into equiaxed grains after annealing. HRTEM photographs indicated that the diffusion between crystalline nickel and TiO2 nanoparticles did happen after annealing. Wear results indicated that the main wear mechanism of as-deposited Ni-TiO2 nanocomposite was adhesion wear. The wear resistance of Ni-TiO2 nanocomposite heat-treated is better than as-deposited Ni-TiO2 nanocomposite because the oxidation layers on the worn surface of Ni-TiO2 nanocomposite masked the strengthening effect of small grain size. The corrosion behavior also has been studied and it is found that annealing reduces the corrosion resistance of composite coatings.

Formation of Grain Structures of Thermal Sprayed Nickel Coatings and the Coating Properties

2005 ◽  
Vol 502 ◽  
pp. 517-0
Author(s):  
Kenji Murakami
Keyword(s):  
Steel Substrate ◽  
Nickel Coatings ◽  
Grain Structures ◽  
Heat Treated ◽  
Columnar Grains ◽  
Different Temperatures ◽  
Plasma Sprayed ◽  
Equiaxed Grains ◽  
Sprayed Coatings ◽  
Lamellar Interfaces

Pure nickel powder was low pressure plasma sprayed onto a steel substrate held at different temperatures during spraying. The as-sprayed coatings consist of columnar grains whose axes are nearly perpendicular to the lamellae composing the coatings. As the coating temperature becomes higher, the length of the columnar grains increases and is longer than the thickness of the lamellae, indicating the growth of the grains across the lamellar interfaces during spraying. On the other hand, the coatings that were heat treated after spraying consist of coarse equiaxed grains. The coatings that experienced high temperatures during spraying or the heat treated coatings have large porosity and contain large globular pores. The hardness, apparent density and the tensile strength of the coating itself were the highest for the coating prepared at a low temperature and became low on heat treatment. The thermal conductivity in the direction perpendicular to the coating was the largest for the coating that consisted of long columnar grains.

Characterization of Ni-P and Ni-P-Al2O3 Heat Treated Layers

2017 ◽  
Vol 1143 ◽  
pp. 26-31
Author(s):  
Lucica Balint ◽  
Gina Genoveva Istrate
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Corrosion Resistance ◽  
Composite Coatings ◽  
Treatment Temperature ◽  
Initial State ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated ◽  
Before And After

Research has shown the relationship among hardness, usage and corrosion resistance Ni-P-Al2O3 composite coatings on steel support heat treated. The electroless strips were heat treated at 200°C, 300°C, 400°C, 500°C and 600°C. Further studies on corrosion, hardness and usage revealed changes in properties, compared to the initial state, both on the strips coated with Ni-P and the ones coated with Ni-P-Al2O3 composite. The samples have been studied before and after the heat treatment via Scanning Electron Microscopy (SEM), Transmission Electron Microscopy (TEM), Energy Dispersive X-ray Analysis (EDX) and X-Ray Diffraction (XRD). The results show that untreated Ni-P layers exhibit strong corrosion resistance, while hardness and usage increase with heat treatment temperature, with a peak at 400 °C. Using suspended particles co-deposition, led to new types of layers, some with excellent hardness and usage properties. Corrosion resistance increase with heat treatment. Coating layers can be adjusted to the desired characteristics, by selecting proper parameters for the expected specific results.

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.

Fresh-cut Mango Fruit Slices

HortScience ◽  
1998 ◽  
Vol 33 (3) ◽  
pp. 457b-457 ◽  
Author(s):  
Arunya Limbanyen ◽  
Jeffrey K. Brecht ◽  
Steven A. Sargent ◽  
Jerry A. Bartz
Keyword(s):  
Chilling Injury ◽  
Flesh Color ◽  
Mango Fruit ◽  
Heat Treated ◽  
Before And After ◽  
Yellow Flesh ◽  
Postharvest Life ◽  
Fresh Cut ◽  
Flesh Browning ◽  
Aseptic Conditions

Preparation and handling procedures for fresh-cut mango slices were developed using `Tommy Atkins', `Haden', and `Palmer' mangoes. Fruit with yellow flesh color (no green color remaining) were optimum maturity for fresh-cut in terms of maintenance of acceptable appearance, texture, and taste; riper fruit developed flesh breakdown and more browning. Postharvest life of fresh-cut mango at 5 °C was 8 to 10 d with no evidence of chilling injury and was limited by flesh browning and loss of firmness. Respiration rates ranged from 32 to 40 mg CO2/kg per hr and ethylene production was typically ≤0.1 μl·kg–1·hr–1. The SSC changed little during storage, while pH varied from 3.5 to 4.8 and TA typically declined by 30% to 40%. Peeling to a depth of at least 2 mm and trimming flesh near the stem scar was necessary to minimize browning. Imported fruit that had been heat-treated for insect quarantine showed more severe browning than Florida fruit that had not been heat-treated. Preparation in aseptic conditions and dipping fruit in a 100 ppm NaOCl solution at pH 7 before and after peeling protected against decay during storage but dipping in chlorine after slicing without removal of excess liquid resulted in flesh translucency and breakdown. Dipping in 1% CaCl2 solution had no effect on flesh firmness (Instron) or browning. Storage in an unvented plastic clamshell container, which developed an atmosphere of 2.25% CO2 plus 19% O2, did not improve shelf life, but a MA of 10% CO2 plus 10% O2 was subjectively judged to slow browning and softening and resulted in no off flavor compared to air storage.

scholarly journals Impedance Spectroscopy of Lead-Free Ferroelectric Coatings

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 221
Author(s):  
Mariya Aleksandrova ◽  
Ivailo Pandiev
Keyword(s):  
Composite Coatings ◽  
Electrical Circuit ◽  
Ferroelectric Materials ◽  
Piezoelectric Transducers ◽  
Lead Free ◽  
Electrical Behavior ◽  
Oxide Composite ◽  
Before And After ◽  
Frequency Dependences ◽  
Good Agreement

This paper presents impedance measurements of ferroelectric structures involving lead-free oxide and polymer-oxide composite coatings for sensing and energy harvesting applications. Three different ferroelectric materials grown by conventional microfabrication technologies on solid or flexible substrates are investigated for their basic resonant characteristics. Equivalent electrical circuit models are applied to all cases to explain the electrical behavior of the structures, according to the materials type and thickness. The analytical results show good agreement with the experiments carried out on a basic types of excited thin-film piezoelectric transducers. Additionally, temperature and frequency dependences of the dielectric permittivity and losses are measured for the polymer-oxide composite device in relation with the surface morphology before and after introduction of the polymer to the functional film.

scholarly journals Wear and Friction Characteristics of 65Mn Steel for Spike-Tooth Harrow

Coatings ◽  
2021 ◽  
Vol 11 (3) ◽  
pp. 319
Author(s):  
Zhiguo Lu ◽  
Chuanyu Du ◽  
Qingcai Chen ◽  
Tianying Niu ◽  
Na Wang ◽  
...  
Keyword(s):  
Friction And Wear ◽  
Working Environment ◽  
Manganese Steel ◽  
Wear Loss ◽  
Variable Parameters ◽  
Wear Characteristics ◽  
Before And After ◽  
Set Up ◽  
Worn Surface ◽  
Friction And Wear Characteristics

The friction and wear characteristics of spike-tooth material (65Mn steel) of Spike-Tooth Harrow in a two-stage peanut harvester were studied in this paper. The friction and wear tests of pin and disc on 65 manganese steel were carried out on the tribometer, then the wear loss and the friction coefficient were studied. The wear loss of the pin was acquired by calculating the mass of the pin before and after the experiment using an electronic balance. According to the actual working environment of peanut spring-finger, four variable parameters are set up: load, speed, soil moisture and soil type. The friction and wear characteristics of pins were studied under different loads, speeds and different soil environments. After wearing, the worn surface of the material was observed by scanning microscope and the wear mechanism was studied. The experimental results show that the wear of the pin increases with the increase of load and decreases with the increase of rotational speed in the same rotation number. Especially in the case of the sandy soil with 20% in moisture, a maximum wear loss of the pin is achieved.

scholarly journals The Effect of Co-Deposition of SiC Sub-Micron Particles and Heat Treatment on Wear Behaviour of Ni–P Coatings

Coatings ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 180
Author(s):  
Donya Ahmadkhaniha ◽  
Lucia Lattanzi ◽  
Fabio Bonora ◽  
Annalisa Fortini ◽  
Mattia Merlin ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Friction Coefficient ◽  
Wear Mechanisms ◽  
Composite Coatings ◽  
Wear Behaviour ◽  
Maximum Hardness ◽  
Sic Particles ◽  
Heat Treated ◽  
The Coefficient Of Friction ◽  
The Difference

The purpose of the study is to assess the influence of SiC particles and heat treatment on the wear behaviour of Ni–P coatings when in contact with a 100Cr6 steel. Addition of reinforcing particles and heat treatment are two common methods to increase Ni–P hardness. Ball-on-disc wear tests coupled with SEM investigations were used to compare as-plated and heat-treated coatings, both pure and composite ones, and to evaluate the wear mechanisms. In the as-plated coatings, the presence of SiC particles determined higher friction coefficient and wear rate than the pure Ni–P coatings, despite the limited increase in hardness, of about 15%. The effect of SiC particles was shown in combination with heat treatment. The maximum hardness in pure Ni–P coating was achieved by heating at 400 °C for 1 h while for composite coatings heating for 2 h at 360 °C was sufficient to obtain the maximum hardness. The difference between the friction coefficient of composite and pure coatings was disclosed by heating at 300 °C for 2 h. In other cases, the coefficient of friction (COF) stabilised at similar values. The wear mechanisms involved were mainly abrasion and tribo-oxidation, with the formation of lubricant Fe oxides produced at the counterpart.

Slip Casting Used as a Forming Technique for Hydroxyapatite Processing

2016 ◽  
Vol 720 ◽  
pp. 219-222 ◽  
Author(s):  
Rubens Lincoln Santana Blazutti Marçal ◽  
Daniel Navarro da Rocha ◽  
Marcelo Henrique Prado da Silva
Keyword(s):  
Slip Casting ◽  
Ceramic Materials ◽  
Processing Route ◽  
Ceramic Suspension ◽  
Polyethylene Glycol 400 ◽  
Density Measurements ◽  
Hydroxyapatite Powder ◽  
Heat Treated ◽  
Thermal Phase ◽  
Before And After

Ceramic materials have particular properties when compared to other classes of materials, exhibiting poor ductility as an example. Slip casting is a widely used ceramic forming technique, and already established in the literature and in the ceramic industry. This study aims to present slip casting as a processing route for producing hydroxyapatite (HA) struts, and show the thermal phase stability. The ceramic suspension was produced and stabilized with hydroxyapatite powder, deionized water and polyethylene glycol 400. The slip was poured into gypsum mold. The green bodies were heat treated at 900 and 1100°C. Hydroxyapatite was the only phase present in all samples, before and after heat treatments. Density measurements showed that the densification was higher for the ceramic bodies sintered at 1100°C, when compared to the ones calcined at 900°C.

scholarly journals Safety and Effectiveness of Additional Apical Preparation using a Rotary Heat-treated Nickel–Titanium file with Larger Diameter and Minimum Taper in Retreatment of Curved Root Canals

2021 ◽  
Author(s):  
Jader Camilo Pinto ◽  
Fernanda Ferrari Esteves Torres ◽  
Airton Oliveira Santos-Junior ◽  
Marco Antonio Hungaro Duarte ◽  
Juliane Maria Guerreiro-Tanomaru ◽  
...  
Keyword(s):  
Fatigue Resistance ◽  
Continuous Wave ◽  
Cyclic Fatigue ◽  
Nickel Titanium ◽  
Filling Material ◽  
Root Canals ◽  
Filling Materials ◽  
Heat Treated ◽  
Before And After ◽  
Curved Root Canals

Abstract Objective The aim of this study was to investigate the effect of additional apical preparation using the ProDesign Logic (PDL) 50/.01 rotary heat-treated nickel–titanium (NiTi) file with a larger diameter and minimal taper for retreatment of curved root canals. Materials and Methods Mesial curved root canals of 12 mandibular molars were prepared using PDL 25/.06 and filled using the continuous wave of condensation technique and AH Plus sealer. After retreatment using ProDesign S (PDS) 25/.08, PDL 25/.06 and PDL 35/05, a complementary procedure was performed with PDL 50/.01. Microcomputed tomography (micro-CT) scanning was performed before and after retreatment procedures. The cyclic fatigue resistance of unused PDS 25/.08, PDL 25/.06, PDL 35/.05 and PDL 50/.01 instruments (n = 12) was evaluated in a stainless-steel device. Statistical Analysis Data on the volumes of the root canals and the remaining filling materials were submitted to the paired t-test. Cyclic fatigue resistance data was submitted to one-way ANOVA and Tukey’s tests (α = 0.05). Results Use of PDL 50/.01 decreased the remaining filling materials in the apical third (p < 0.05). The root canal volume was similar in the cervical and middle thirds before and after preparation using PDL 50/.01 (p > 0.05). PDL 50/.01 presented the highest cyclic fatigue resistance (p < 0.05). Conclusions Use of the PDL 50/.01 instrument as an additional apical preparation for retreatment of curved root canals improved filling material removal in the apical third, while maintaining the dentin in the cervical and middle thirds. In addition, PDL 50/.01 presented high-flexural resistance.

Application of Thermo-Frictional and Chemical-Thermal Methods Treatments for Surface Strengthening of Materials

2021 ◽  
Vol 1038 ◽  
pp. 93-99
Author(s):  
Alexander Levterov ◽  
Julia Nechitailo ◽  
Tatyana Plugina ◽  
Oleg Volkov
Keyword(s):  
Cross Sections ◽  
Experimental Studies ◽  
Metallographic Analysis ◽  
Thermal Treatments ◽  
Strengthening Effect ◽  
Thermal Methods ◽  
Surface Strengthening ◽  
Before And After ◽  
The Cross

In the article, the issues of using the methods of thermo-frictional and chemical-thermal treatments for surface strengthening of steel tools were disclosed. 65G steel and U8A steel were considered. A flat graver and a cylindrical root roller were considered to be tools in need of hardening. The nature of the jewellery work using such a tool has been described. Hardening techniques, experimental studies and macro photographs of the samples were presented in this article. A detailed metallographic analysis and measurement of the microhardness of the cross-sections of the prototypes after their strengthening using various methods was carried out. The metallographic nature of the reinforcement with the formation of surface "white layers" was shown. Comparison of the properties of the samples before and after strengthening was carried out. Conclusions about the strengthening effect of the thermo-frictional and chemical-thermal methods of strengthening were made.

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