Determination of Adhesive and Cohesive Strength in Metal Coatings Deposited by Hypersonic Metallization

. It is known that at present, methods of thermal spraying are widely used to restore and strengthen various worn-out machine parts. As a rule, metal coatings applied by thermal spraying have lower strength characteristics than solid materials. It is believed that the strength of coatings is proportional to their adhesive and cohesive strength. The value of adhesive and cohesive strength depends on various factors, including the nature of the materials and the technology of coating. An important factor characterizing the possibility of using metal coatings in various industries is the strength of adhesion of coatings to the base metal. The paper presents the determination of the adhesive and cohesive strength of coatings from different materials, applied by the method of hypersonic metallization. The results of testing the strength of metal coatings made of ER316LSi-grade wire, nichrome (Cr20Ni80) and molybdenum wire are given in the paper. Based on the results of metallographic studies, the proportion of the participation of cohesive and adhesive components in the strength of coatings has been determined, and some features of coating destruction have been described. It has been found that the participation of the cohesive and adhesive components of the coating strength differs depending on the material used. The cohesive component prevails in the strength of coatings made of high-alloy wire of the ER316LSi-grade, at which destruction mainly occurs along the coating-base boundary. For nichrome coatings and especially for coatings made of molybdenum, the cohesive component is predominant, in which the destruction of the coating occurs not along the coating-base boundary, but between the coating layers.

How Did the Base Work?

We now consider how the military base area operated, as a zone where a large number of people lived and worked on a routine basis. On one hand, to function it required the affordances of its internal communications, connections with the civil town, and access to roads, river, and lands beyond the walls; on the other, there was a need for surveillance and control of activities within the base, and of movements across its boundary. The most obvious part of the base boundary (Plate XXII) is the substantial mud brick wall ploughed across four blocks from the city defences just S of Tower 21, and blocking Wall, A, C, and D Sts, with a gate established at B St. How the S boundary was defined E of D St has always remained an issue. If it was necessary to build a wall at the W end, why was this not simply continued all the way to, e.g., the S end of the Citadel? Across blocks F7 and F5 it seems that the boundary of the military zone simply comprised party walls between military and civilian-occupied structures. The same was true within block B2, by the Citadel, although the boundary probably comprised building frontages along Lower Main St. On the plateau, as the camp wall may have been a subsequent local enhancement, except where the amphitheatre formed part of it, the boundary may generally have comprised the rear walls of military-held houses lining the S side of 8th St—probably all properties from the city wall to H St. The course of the boundary along the W side of the inner wadi is unknown, but the base is suggested, as along 8th St, to have incorporated at least all properties lining the S side of the Wadi Ascent Road, if not encompassing all blocks on the wadi slope—in which case the boundary here may rather have comprised property frontages on K St. The base area was split by site topography into two major zones, the flat plateau, and the N branch of the inner wadi around the Citadel. Each was further subdivided.

Distribution and glaciological implications of relict surfaces on the Ultevis plateau, northwestern Sweden

The Ultevis plateau, northwestern Sweden, has a relief of less than 200 m, yet bears three different kinds of landscape, classified according to the degree of glacial erosion. The first type is restricted mainly to topographic highs and has almost entirely escaped erosion, despite complete and prolonged ice cover during the late Weichselian. The other two landscape types are distinguished depending on whether older land- forms have been completely erased or not. The latter two appear to have undergone erosion only briefly. The transitions between landscape zones are usually sharp, and specific boundary landforms occur. The Scandinavian ice sheet was cold-based in its central areas during its maximum. During the deglaciation, both the dry/wet-base boundary and ice margin migrated inwards, at different speeds. When the ice front retreated faster than the thermal transition zone, the wet-base marginal zone shrank and erosion was reduced or avoided. Where the wet-base zone was of limited longitudinal extent, as on the Ultevis plateau, conversion from a frozen to a thawed bed was incomplete, leaving a patchwork of preserved glacial and non-glacial morphologies.

A heat flow profile across the Sverdrup Basin, Canadian Arctic Islands

An average geothermal gradient of 25 ± 5 mK/m and an average heat flow of [Formula: see text] have been determined for 16 out of 20 analyzed wells along a profile across the Sverdrup Basin in the Canadian Arctic. These estimates, based on deep bottom‐hole temperature (BHT) data from exploration wells and the permafrost base boundary temperature, together with assumed heat conductivities from net rock analysis, are surprisingly low and disagree with previously published results based on shallow data. The differences may be due to the dramatic changes in boundary temperature conditions from moderate subsea conditions to ground‐surface low temperatures as a result of marine regression. Because of these effects, it appears that deep BHT temperature data are valuable in providing information about the deep heat flow. The heat flows thus determined indicate that the basin has approached thermal equilibrium.