Ridge Formation during the Abrasion of Elastomers

1982 ◽  
Vol 55 (4) ◽  
pp. 1055-1062 ◽  
Author(s):  
A. K. Bhowmick
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Natural Rubber ◽  
Crack Growth ◽  
Unit Length ◽  
Crack Growth Resistance ◽  
Small Particles ◽  
The Matrix ◽  
Natural Rubber Vulcanizates ◽  
Scanning Electron

Abstract Scanning electron microscopy studies have been carried out on gum and filled natural rubber vulcanizates to investigate the ridge formation in the abrasion of elastomers. The first step of the ridge formation is the occurrence of small particles on the smooth abrading surface by a process of microtearing. Their size and shape depend upon the frictional force per unit length of the abrader in contact with the rubber and the nature of the rubber and the abrasive. These particles are not loose, and, hence, are not removed easily if the strength of the matrix is high. Further particles appear on the surface with continued abrasion. These particles coalesce to form fine ridges on the surface which become progressively thicker. Removal of these ridges depends upon the crack growth resistance and strength of the vulcanizate as well as on the dissipation of sliding energy in the matrix. Gum and filled natural rubber vulcanizates follow similar mechanisms of ridge formation. Due to low strength and crack growth resistance of the gum natural rubber, the abrasion resistance is poor compared to the filled ones.

Scanning Electron Microscopy Studies of Fractured Natural Rubber Surfaces

1980 ◽  
Vol 53 (2) ◽  
pp. 327-334 ◽  
Author(s):  
A. K. Bhowmick ◽  
G. B. Nando ◽  
S. Basu ◽  
S. K. De
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Natural Rubber ◽  
Polymer Chains ◽  
Flow Lines ◽  
Filler Surface ◽  
The Matrix ◽  
Scanning Electron

Abstract A tensile ruptured gum specimen shows formation of crystalline regions at an angle of 45° to the flow lines, whereas a tensile ruptured filled specimen shows formation of depression. A tear fractured gum specimen shows again the formation of crystallites at an angle of 45° to the flow lines. Tear fractured filled specimens show the enhancement of crystallinity throughout the matrix, but the surface is rough. Flex fractured gum specimen show a large number of cracks on the surface while the filled vulcanizate shows formation of balls presumably due to coiling of polymer chains on the filler surface. An abraded gum surface shows dimple structure, while a filled vulcanizate indicates coarse ribbed structure. Addition of lignin, in general, reduces the crystallinity of tensile and tear fractured samples and increases the fibrosity of flex cracked and abraded samples.

Characteristics of Ni–Cr–Fe laser clad layers on EA4T steel

2017 ◽  
Vol 31 (16-19) ◽  
pp. 1744031
Author(s):  
Wenjing Chen ◽  
Hui Chen ◽  
Yongjing Wang ◽  
Congchen Li ◽  
Xiaoli Wang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
X Ray Diffraction ◽  
X Ray ◽  
Cladding Layer ◽  
Metallurgical Bonding ◽  
The Matrix ◽  
Feeding Speed ◽  
Upper Bainite ◽  
Scanning Electron

The Ni–Cr–Fe metal powder was deposited on EA4T steel by laser cladding technology. The microstructure and chemical composition of the cladding layer were analyzed by optical microscopy (OM), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The bonding ability between the cladding layer and the matrix was measured. The results showed that the bonding between the cladding layer and the EA4T steel was metallurgical bonding. The microstructure of cladding layer was composed of planar crystals, columnar crystals and dendrite, which consisted of Cr2Ni3, [Formula: see text] phase, M[Formula: see text]C6 and Ni3B phases. When the powder feeding speed reached 4 g/min, the upper bainite occurred in the heat affected zone (HAZ). Moreover, the tensile strength of the joint increased, while the yield strength and the ductility decreased.

Tensile Property of the Flax/Polyester Composites after Water Treatment

2011 ◽  
Vol 194-196 ◽  
pp. 1740-1744 ◽  
Author(s):  
Qiu Hong Wang ◽  
Gu Huang
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Tensile Strength ◽  
Water Treatment ◽  
Tensile Property ◽  
Unsaturated Polyester ◽  
Water Immersion ◽  
The Matrix ◽  
Polyester Composites ◽  
Scanning Electron

Flax fabric was woven and composites were produced by using the VARI technique with flax fabric as the reinforcement and unsaturated polyester as the matrix. Laminates with two, three and four layers were fabricated respectively. After saturated in the water for different durations of time (7, 14, 21 and 30 days), the tensile strength of the composites was tested. After being soaked in the water for 7, 14 and 21 days, the tensile strength of the two-layer composites was decreased. For the three and four layers specimens, the tensile strength was increased initially with water treatment for 7 and 14 days,and decreased for 21 and 30 days. Scanning electron microscopy (SEM) confirmed that it might be contributed to the thickness of the two-layer composites. The thinner specimen is easier to be damaged by the penetrated moisture owing to the delamination between the fiber and the matrix after water immersion. For the three and four layers specimens, their contradictory tensile strength suggests that the thicker specimen can delay the moisture permeation and is of better water durability.

The Impact Properties of a Polyurethane Composite Filled with Clay

2011 ◽  
Vol 197-198 ◽  
pp. 1100-1103
Author(s):  
Jian Li
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Mechanical Analysis ◽  
Impact Testing ◽  
Impact Properties ◽  
Polyurethane Composite ◽  
The Matrix ◽  
The Impact ◽  
Scanning Electron

A polyurethane/clay (PU/clay) composite was synthesized. The microstructure of the composite was examined by scanning electron microscopy. The impact properties of the composite were characterized by impact testing. The study on the structure of the composite showed that clays could be dispersed in the polymer matrix well apart from a few of clusters. The results from mechanical analysis indicated that the impact properties of the composite were increased greatly in comparison with pure polyurethane. The investigation on the mechanical properties showed that the impact strength could be obviously increased by adding 20 wt% (by weight) clay to the matrix.

scholarly journals The Influence of A Mo Addition on the Interfacial Morphologies and Corrosion Resistances of Novel Fe-Cr-B Alloys Immersed in Molten Aluminum

Materials ◽  
2019 ◽  
Vol 12 (2) ◽  
pp. 256 ◽  
Author(s):  
Zicheng Ling ◽  
Weiping Chen ◽  
Weiye Xu ◽  
Xianman Zhang ◽  
Tiwen Lu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Electron Probe ◽  
Molten Aluminum ◽  
Dendritic Structure ◽  
H13 Steel ◽  
X Ray ◽  
Transmission Electron ◽  
The Matrix ◽  
Scanning Electron

The influence of a Mo addition on the interfacial morphologies and corrosion resistances of novel Fe-Cr-B alloys in molten aluminum at 750 °C was systematically investigated using scanning electron microscopy, X-ray diffractometer, electron probe microanalysis, and transmission electron microscopy. The results indicated that Mo could not only strengthen the matrix but also facilitate the formation of borides. Furthermore, the microstructures of Mo-rich M2B boride changed from a local eutectic net-like structure to a typical coarse dendritic structure and a blocky hypereutectic structure with increasing Mo addition. This was true of the blocky Mo-rich M2B boride, rod-like Cr-rich M2B boride and the corrosion products, which had a synergistic effect on retarding of the diffusion of molten aluminum. Notably, the corrosion resistance of the Fe-Cr-B-Mo alloy, with an 8.3 wt.% Mo addition, was 3.8 times higher than that of H13 steel.

Influence of the Treatment with Sulfuric Acid on Adhesion of Natural Rubber and Cast Polyurethane Elastomers

2012 ◽  
Vol 452-453 ◽  
pp. 86-90 ◽  
Author(s):  
Zhi Yi Zhang ◽  
Hui Jun Niu ◽  
Jia Jia Zhang ◽  
Yan Yun Cui
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Contact Angle ◽  
Sulfuric Acid ◽  
Natural Rubber ◽  
Angle Measurement ◽  
Polyurethane Elastomers ◽  
Adhesion Properties ◽  
Rubber Surface ◽  
Scanning Electron

In this study, natural rubber (NR) was treated with sulfuric acid to improve its adhesion properties to polar polymer. T-peel strength tests, scanning electron microscopy, contact-angle measurement (water), Energy Dispersive X-ray Detector were used to analyze the nature of the NR surface modifications which were carried out with sulfuric acid. A noticeable decrease in contact angle was observed on the rubber surface by contact-angle measurements which can be ascribed to the increase of oxidized moieties on the rubber surface. EDX revealed that oxidized moieties were created through treatment with sulfuric acid. The surface modification and mode of bond failure were studied by scanning electron microscopy (SEM). Immersion in sulfuric acid for 15min produced the maximum adhesion strength (10kN/m) and produced a mixed failure mode (interface & rubber failure in the rubber). Treatment with sulfuric acid produced improved wettability as well as chemical (surface oxidation) and morphological modifications (roughness) of the rubber surface.

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