Reduction and carbonitriding of anodic titanium oxide film by using a mixture of iron and carbon powders

Yoshimoto, Mitsutaka; Agawa, Shinzi; Morizono, Yasuhiro; Tsurekawa, Sadahiro

doi:10.2109/jcersj2.123.903

Cited by 4 publications

(5 citation statements)

References 7 publications

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“…In IPP treatment, carbon monoxide (CO) gas is generated near 973 K in a heating step. [13][14][15] This is probably due to the chemical reaction between the carbon in the powder mixture and residual oxygen in the electric furnace. Oxygen in the furnace is probably expelled because CO is released with the nitrogen ow from the furnace exhaust.…”

Section: Heating Temperaturementioning

confidence: 99%

“…The greatest advantage of our method is that the iron powder is added to the carbon powder, leading to a lower process temperature than the method proposed by Matsuura et al 12) We propose that the iron powder increases the carbon movement in the powder mixture, like a catalyst. Our technique also enables the reduction and carbonitriding of an oxide lm on anodized titanium, 14) and the diffusion of carbon and nitrogen into stainless steel. 15) We call this technique iron-powder pack (IPP) treatment , and we are verifying its practical effectiveness.…”

Section: Introductionmentioning

confidence: 99%

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Effect of Heating Conditions on Surface Modification of Titanium with a Mixture of Iron, Graphite and Alumina Powders

et al. 2017

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We developed a new surface modi cation technique called iron-powder pack (IPP) treatment. A layer of titanium carbonitride, Ti(C, N), was formed on the surface of a titanium sample embedded in a mixture of iron, graphite, and alumina powders and held around 1273 K in a nitrogen ow. In this work, IPP treatment using a 4:6:3 (volume ratio) mixture of iron, graphite, and alumina powders was applied to titanium plates, and the effects of the heating temperature and nitrogen gas ow rate on the microstructures near the titanium surface were investigated. The Ti(C, N) layer was observed on the titanium plate heat-treated at 1173 K for 3.6 ks at a nitrogen ow rate of 0.5 L/min. This layer became uniform and thick as the heating temperature increased. At 1373 K, a Ti(C, N) layer with a thickness of more than 30 μm that increased the hardness of the titanium surface to an HV value of about 1500 was obtained. In addition, an increase in the nitrogen ow rate increased the surface hardness further. Spherical titanium powder was treated at 1273 K to examine the growth of the Ti(C, N) layer. The layer thickness increased with the holding time. Because the average diameter of the spherical powder was unchanged after heating, the Ti(C, N) layer grew toward the inside of the titanium via the diffusion of carbon and nitrogen from the powder mixture and the atmosphere.

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Section: Heating Temperaturementioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Effect of Heating Conditions on Surface Modification of Titanium with a Mixture of Iron, Graphite and Alumina Powders

et al. 2017

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“…The authors have reported a novel surface modification technique called "iron-powder pack (IPP) treatment", [7][8][9] wherein stainless steel is carburized. 7) In particular, a steel pipe, which is packed with a stainless steel specimen and a mixture of iron and carbon powders, is heated at 1 273 K for 3.6 ks in a nitrogen flow and then cooled rapidly in water.…”

Section: Introductionmentioning

confidence: 99%

Surface Modification of Ferritic Stainless Steel by Heating in Iron, Graphite and Alumina Powders

2020

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A new surface modification technique, called "iron-powder pack (IPP) treatment", has been proposed. During IPP treatment, carbon and nitrogen diffuse into a metal substrate by treating it with a mixture of iron and carbon powders at high temperature in a nitrogen flow. This paper describes the effects of adding alumina to the mixture of iron and graphite powders on the microstructures and hardness of SUS430 ferritic stainless steel after IPP treatment. The alumina powder was added to prevent powder mixtures from sintering. A 7:3 (volume ratio) mixture of iron and graphite powders was used as a "base powder", and the volume ratio of the alumina powder added to the base powder was varied from 0:1 to 50:1. A steel pipe packed with SUS430 steel and powder was heat-treated at 1 273 K for 3.6 ks in a nitrogen flow and then rapidly cooled in water. A surface-modified layer formed on the SUS430 steel through IPP treatment. When IPP treatment was performed using only the base powder, carbon was detected in the surface-modified layer. Both carbon and nitrogen diffused when alumina was added to the base powder. However, the thickness of the surface-modified layer gradually decreased from 380 to 125 μm with an increase in the amount of alumina. A similar tendency was observed in the surface hardness of the steel. In addition, the effects of subzero treatment and immersion in an aqueous nitric acid solution on the modified steel are discussed.

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“…In addition, this technique enables the formation of a Ti(C, N) layer on a metallic titanium substrate 11) and the reduction and carbonitriding of an oxide film on an anodized titanium substrate. 12) We have named this carbon and nitrogen diffusion technique "ironpowder pack (IPP) treatment". The feature of the IPP treatment is that carbon monoxide (CO) gas is generated in a heating step.…”

Section: Introductionmentioning

confidence: 99%

“…The feature of the IPP treatment is that carbon monoxide (CO) gas is generated in a heating step. [10][11][12] This is probably due to a chemical reaction between carbon in the powder mixture and residual oxygen in an electric furnace. Oxygen in the furnace should be expelled, because the CO gas is exhausted with a nitrogen flow from the furnace.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Changes in Low-carbon Steel Occurring by Heating in Mixtures of Iron, Graphite and Alumina Powders

2018

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Carbon and nitrogen are easily diffused into stainless steel and titanium, when these are embedded in mixtures of iron, graphite and alumina powders and held at high temperatures in a nitrogen flow. To promote an understanding of this new diffusion technique, which we call "iron-powder pack treatment", we focused attention on the microstructures of low-carbon steel subjected to such a treatment. The diffusion of carbon into the steel was understood by evaluating area fraction of pearlite emerging in ferrite. A pearlite area in the steel, which was heat-treated at 1 273 K for 3.6 ks using a mixture of iron and alumina powders, was larger than before heating, because the steel was carburized by carbon in the iron powder. On the other hand, an increase in the pearlite area was hardly observed in the case of a mixture of graphite and alumina powders. By replacing a part of graphite in this mixture with the iron powder, however, pearlite was most remarkably produced in the steel. Instead of the iron powder, the use of nickel powder did not exert a significant impact on the diffusion of carbon into the steel. These indicate that the iron powder acts as an important agent for enhancing the migration of carbon from a powder mixture to lowcarbon steel. The relationship between a diffusion phenomenon of carbon and the generation of carbon monoxide gas in heat treatment is also discussed.

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Reduction and carbonitriding of anodic titanium oxide film by using a mixture of iron and carbon powders

Cited by 4 publications

References 7 publications

Effect of Heating Conditions on Surface Modification of Titanium with a Mixture of Iron, Graphite and Alumina Powders

Effect of Heating Conditions on Surface Modification of Titanium with a Mixture of Iron, Graphite and Alumina Powders

Surface Modification of Ferritic Stainless Steel by Heating in Iron, Graphite and Alumina Powders

Microstructural Changes in Low-carbon Steel Occurring by Heating in Mixtures of Iron, Graphite and Alumina Powders

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