Corrosion Behavior of Sintered Silicon Nitride Ceramics in Acid and Alkaline Solutions

Arai, Masatsugu; Kohno, Akiomi

doi:10.3323/jcorr1991.44.276

Cited by 6 publications

(7 citation statements)

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“…The mechanisms underlying corrosion in bases and under hydrothermal conditions are the same, but different to the mechanism in acids. For standard Si 3 N 4 materials, the weight loss and the corrosion depth are much lower in bases at least up to concentrations of 1 mol/l and temperatures up to 130°C than in acids . Figure provides an example of the weight loss and change in strength in 1 and 4 N NaOH to illustrate this fact.…”

Section: Corrosion Of Si3n4 Materials With Sintering Additivesmentioning

confidence: 96%

“…Numerous different investigations of silicon nitride materials in acids have been carried out . Sometimes it is difficult to compare the data directly because the composition is not always completely described, or the conditions of corrosion, especially the ratio of the sample volume or surface to the volume of the used solution, are not always clear.…”

Section: Corrosion Of Si3n4 Materials With Sintering Additivesmentioning

confidence: 99%

“…Investigation of the corrosion stability of these ceramics in aqueous media started in the 1990s due to the increasing use of the material in ball bearings . These investigations revealed the strong relationship between the grain‐boundary phase and the chemical stability, but a more systematic investigation and derivation of the correlation between composition and microstructure with the corrosion properties in the different media only occurred at the beginning of the 21st century.…”

Section: Introductionmentioning

confidence: 99%

“…Investigation of the corrosion stability of these ceramics in aqueous media started in the 1990s due to the increasing use of the material in ball bearings. [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] These investigations revealed the strong relationship between the grain-boundary phase and the chemical stability, but a more systematic investigation and derivation of the correlation between composition and microstructure with the corrosion properties in the different media only occurred at the beginning of the 21st century. The aim of this study was to give an overview of the work carried out in the field of corrosion and, based on these results, discuss guidelines for the design of corrosionresistant materials.…”

Section: Introductionmentioning

confidence: 99%

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Corrosion of Silicon Nitride Materials in Aqueous Solutions

Herrmann

2013

J. Am. Ceram. Soc.

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Silicon nitride ceramics are used under conditions where high strength, hardness, and wear resistance are necessary. The increasing use of Si3N4 ceramics in different environments demands an understanding of the relationships between microstructure and corrosion behavior. This study gives an overview of the behavior of silicon nitride in acids, bases, and hydrothermal conditions. It not only summarizes the literature data but also attempts to explain the mechanisms and to give some guidelines for the use of the materials in different environments. The stability of the ceramics against corrosion in acids and bases up to the boiling point is mostly controlled by the stability of the grain boundary. The stability can be predicted using the glass network theory. Materials with grain boundaries exhibiting a strong network, i.e., a high amount of SiO2 in the grain boundary, are stable in acids, but less stable under hydrothermal conditions and in basic solutions. Therefore, tailoring the grain boundaries can change the corrosion stability by several orders of magnitude. At temperatures above 200°C–250°C, the dissolution of the Si3N4 grains becomes a decisive factor determining the stability.

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Section: Corrosion Of Si3n4 Materials With Sintering Additivesmentioning

confidence: 96%

Section: Corrosion Of Si3n4 Materials With Sintering Additivesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Corrosion of Silicon Nitride Materials in Aqueous Solutions

Herrmann

2013

J. Am. Ceram. Soc.

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“…However, the slopes of the linear correlations for the three kinds of specimen differ, and the correlations for all specimens cannot be summarized by applying one first-order equation. It has been reported that the variation in bending strength of Si 3 N 4 immersed in HCl aqueous solution corresponds well to the supposed existence of semi-circular surface cracks (with diameter D) with equal depth to the thickness of the corroded layer in which grain boundaries are eluted (Arai, et al, 1995). In the present report too, on the basis of that result, the corroded layer in which grain boundaries are prominently eluted is correlated with bending strength under this assumption of the existence of semi-circular surface cracks.…”

Section: Effect Of Corrosion Degradation On Reduction Of Bending Strementioning

confidence: 75%

Degradation of bending strength occurred by corrosion of sintered silicon nitride in aqueous acidic solutions

Arai

2018

Mechanical Engineering Journal

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Three silicon-nitride (Si 3 N 4 ) ceramic specimens (differing in terms of sintering additive and bending strength) were corroded and tested in 3-mol/L-HCl aqueous solutions at 80℃ for 1500 h. The corrosion resistance of each specimen was evaluated by measuring weight loss and bending strength of the specimens before and after the immersion tests. The corroded and fractured surfaces of the specimens were observed by SEM. When the specimens were soaked in the aqueous HCl solutions, weight loss and bending strength decreased with immersion time. Moreover, after immersion, the color of a layer in the fractured section (called "discolored layer" hereafter) changed, and the layer became thicker with immersion time. The discolored layer included a corroded layer at the point of contact with the corrosion solution (where grain boundaries were eluted). The correlation between corroded-layer thickness and weight loss and that between bending strength and weight loss were both found to be linear. However, the gradients of those correlations for each test specimen were found to differ, so it is difficult to summarize these correlations with one linear mathematical expression. Measured bending strength and bending strength predicted using fracture toughness (K IC ) of the Si 3 N 4 -ceramic specimens and crack length were found to be closely related. In this prediction, the corroded-layer thickness of the specimens immersed in HCl solutions was considered to be equivalent to the diameter of semi-circular surface cracks.

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