{"id":8489,"date":"2026-08-14T10:39:27","date_gmt":"2026-08-14T03:39:27","guid":{"rendered":"https:\/\/giaanh.vn\/?post_type=kien-thuc&#038;p=8489"},"modified":"2026-10-08T14:28:17","modified_gmt":"2026-10-08T07:28:17","slug":"part-4-selecting-slide-promotion-materials-and-when-both-functions-are-required","status":"publish","type":"kien-thuc","link":"https:\/\/giaanh.vn\/en\/knowledge\/selecting-anti-adhesion-materials-for-material-build-up-and-flow-blockage\/","title":{"rendered":"Part 4: Selecting anti-adhesion materials for material build-up and flow blockage"},"content":{"rendered":"<p>In wear-related applications, the objective is usually to select a material with suitable properties to reduce the gradual loss of the working surface during operation.<\/p>\n<p>Material build-up and flow blockage follow a very different selection logic. In this case, the lining material is not being worn away. Instead, <strong>bulk material accumulates on the surface<\/strong>. As the build-up becomes thicker, the flow cross-section becomes smaller, throughput decreases, and the risk of blockage gradually increases.<\/p>\n<p>For this reason, increasing hardness does not directly solve the problem. Material selection needs to focus instead on factors related to <strong>anti-adhesion performance, surface energy, material moisture and the actual sliding angle<\/strong>.<\/p>\n<h2><span style=\"color: #970d34;\">1. Wear protection and anti-adhesion are two different problems<\/span><\/h2>\n<p>These two problems have different selection objectives:<\/p>\n<div>\n<div>\n<div>\n<table>\n<thead>\n<tr>\n<th><strong>Aspect to consider<\/strong><\/th>\n<th><strong>Wear protection<\/strong><\/th>\n<th><strong>Anti-adhesion<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>Primary objective<\/strong><\/td>\n<td>Reduce material loss from the working surface<\/td>\n<td>Reduce material build-up and maintain material flow<\/td>\n<\/tr>\n<tr>\n<td><strong>Key properties<\/strong><\/td>\n<td>Hardness, toughness and appropriate wear-resistant properties<\/td>\n<td>Sliding properties, surface energy and flow conditions<\/td>\n<\/tr>\n<tr>\n<td><strong>Surface condition<\/strong><\/td>\n<td>The lining material is gradually worn away<\/td>\n<td>Bulk material accumulates on the surface<\/td>\n<\/tr>\n<tr>\n<td><strong>Main engineering problem<\/strong><\/td>\n<td>Wear mechanism<\/td>\n<td>Material flow and adhesion tendency<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>The key distinction is that <strong>hardness and low adhesion are not the same property<\/strong>.<\/p>\n<p>A very hard material may still allow moist bulk material to adhere strongly. Conversely, a material with lower hardness may reduce build-up if its surface properties are better suited to the material being handled.<\/p>\n<p>You can learn more about the formation of build-up, arching and ratholing in <span style=\"color: #3366ff;\"><a style=\"color: #3366ff;\" href=\"https:\/\/giaanh.vn\/en\/knowledge\/material-adhesion-and-flow-blockage\/\"><strong>Part 3: Material build-up and flow blockage: formation mechanisms and identification signs<\/strong><\/a><\/span> in the Material Wear Mechanisms knowledge series.<\/p>\n<h2><span style=\"color: #970d34;\">2. Low surface roughness and anti-adhesion performance are not the same property<\/span><\/h2>\n<p>These two concepts are often treated as if they were the same.<\/p>\n<p><strong>Low surface roughness<\/strong> describes the geometric condition of a surface and can help dry particles slide more easily.<\/p>\n<p><strong>Surface energy<\/strong>, on the other hand, relates to the interaction between moist bulk material and the surface. A very smooth surface can still retain material if its surface characteristics are not suitable for the material being handled.<\/p>\n<p>The four concepts can be separated as follows:<\/p>\n<ul>\n<li><strong>hard<\/strong>: resistance to mechanical action<\/li>\n<li><strong>soft<\/strong>: a lower level of hardness<\/li>\n<li><strong>smooth<\/strong>: low surface roughness<\/li>\n<li><strong>low adhesion<\/strong>: ability to limit material build-up on a surface under specific conditions<\/li>\n<\/ul>\n<p>These four concepts are not interchangeable.<\/p>\n<p>For example, a stone surface may be very hard and polished smooth but still retain wet mud. In contrast, a softer polymer surface may allow the mud to slide more easily because of different surface characteristics.<\/p>\n<h2><span style=\"color: #970d34;\">3. Adhesive wear must be distinguished from material adhesion and flow blockage from the beginning<\/span><\/h2>\n<p>In Vietnamese, the same word \u201cd\u00ednh\u201d may be used for two different phenomena.<\/p>\n<div>\n<div>\n<div>\n<table>\n<thead>\n<tr>\n<th><strong>Concept<\/strong><\/th>\n<th><strong>Mechanism<\/strong><\/th>\n<th><strong>Selection approach<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>Adhesive wear<\/strong><\/td>\n<td>Local adhesion occurs between two contacting surfaces, followed by material transfer<\/td>\n<td>Select materials according to the wear mechanism<\/td>\n<\/tr>\n<tr>\n<td><strong>Material adhesion and flow blockage<\/strong><\/td>\n<td>Bulk material accumulates on the surface and obstructs flow<\/td>\n<td>Select anti-adhesion materials or address the flow conditions<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>If these two concepts are confused, the selection approach may be incorrect from the very beginning.<\/p>\n<p>For flow blockage, the objective is not to increase wear resistance. The objective is to <strong>reduce material adhesion and maintain material flow<\/strong>.<\/p>\n<h2><span style=\"color: #970d34;\">4. Temperature remains an exclusion criterion before anti-adhesion performance is compared<\/span><\/h2>\n<p>Even when adhesion is the primary problem, temperature still needs to be checked first.<\/p>\n<p>A material group may provide good anti-adhesion performance, but if the operating temperature exceeds its allowable limit, it should no longer remain under consideration.<\/p>\n<div>\n<div>\n<div>\n<table>\n<thead>\n<tr>\n<th><strong>Material group<\/strong><\/th>\n<th><strong>Relative anti-adhesion performance<\/strong><\/th>\n<th><strong>Reference temperature limit<\/strong><\/th>\n<th><strong>Relative impact resistance<\/strong><\/th>\n<th><strong>Conditions where it may be considered<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>Ultra-high-molecular-weight polyethylene (PE-UHMW)<\/strong><\/td>\n<td>+++++<\/td>\n<td>80 \u00b0C<\/td>\n<td>Not rated<\/td>\n<td>Moist bulk material, low temperature, no significant impact<\/td>\n<\/tr>\n<tr>\n<td><strong>Smooth stainless steel<\/strong><\/td>\n<td>+++<\/td>\n<td>550 \u00b0C<\/td>\n<td>++<\/td>\n<td>Combined wear and material adhesion<\/td>\n<\/tr>\n<tr>\n<td><strong>Cast ceramic<\/strong><\/td>\n<td>+++<\/td>\n<td>350 \u00b0C<\/td>\n<td>Not rated<\/td>\n<td>Applications requiring both anti-adhesion and wear resistance<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>Ultra-high-molecular-weight polyethylene (PE-UHMW) provides the highest anti-adhesion performance in this table, but it also has <strong>the lowest temperature limit, approximately 80 \u00b0C<\/strong>.<\/p>\n<p>Therefore, the material group with the most favorable surface properties for material flow is not necessarily the most suitable group for all operating conditions at the location.<\/p>\n<p>These values are intended only for initial material-group screening. When selecting a specific grade, the current technical data sheet for that grade must be checked.<\/p>\n<h2><span style=\"color: #970d34;\">5. Moisture, adhesiveness and sliding angle should be evaluated together<\/span><\/h2>\n<p>Material adhesion requires its own set of operating data.<\/p>\n<p>Three parameters should be considered:<\/p>\n<div>\n<div>\n<div>\n<table>\n<thead>\n<tr>\n<th><strong>Parameter<\/strong><\/th>\n<th><strong>Information to determine<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>Material moisture<\/strong><\/td>\n<td>Conditions that promote liquid bridging and build-up formation<\/td>\n<\/tr>\n<tr>\n<td><strong>Adhesiveness<\/strong><\/td>\n<td>Degree of interaction between the bulk material and the surface<\/td>\n<\/tr>\n<tr>\n<td><strong>Sliding angle<\/strong><\/td>\n<td>Geometric condition at which the material begins to move<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>These three parameters should be evaluated together.<\/p>\n<p>If moisture is the main cause, changing the lining material may not address the source of the build-up.<\/p>\n<p>If interaction between the bulk material and the surface is the dominant factor, Anti-adhesion Plastic may be worth considering.<\/p>\n<p>If the angle or equipment geometry is the main cause, the problem needs to shift toward flow-design evaluation.<\/p>\n<p>You can learn more about how these three parameters are measured and used in <span style=\"color: #3366ff;\"><a style=\"color: #3366ff;\" href=\"https:\/\/giaanh.vn\/en\/knowledge\/3-indicators-for-evaluating-material-adhesion\/\"><strong>Part 4: Three parameters for evaluating material adhesion: moisture, adhesiveness and sliding angle<\/strong><\/a><\/span> in the Material Wear Mechanisms knowledge series.<\/p>\n<h2><span style=\"color: #970d34;\">6. Seasonal conditions should be included in the selection process<\/span><\/h2>\n<p>The moisture content of bulk material can vary significantly by season.<\/p>\n<p>A location that experiences little blockage during the dry season but frequent blockage during the rainy season should not be evaluated based only on a single measurement taken under favorable conditions.<\/p>\n<p>The inspection record should include:<\/p>\n<ul>\n<li>date of survey<\/li>\n<li>season in which the survey was conducted<\/li>\n<li>material moisture at the time of measurement<\/li>\n<li>season in which the most severe blockage occurs, based on operating data<\/li>\n<\/ul>\n<p>Dry-season data should not be treated as representative of rainy-season conditions when the condition of the material changes significantly.<\/p>\n<p>If a survey cannot be carried out during the most severe season, the representative limits of the available data should be clearly stated rather than using that data to infer conditions in another season.<\/p>\n<h2><span style=\"color: #970d34;\">7. When wear and material adhesion occur together, there are three main approaches<\/span><\/h2>\n<p>A location may be exposed to both particle wear and material build-up on the surface.<\/p>\n<p>When both requirements exist, there are three main approaches:<\/p>\n<div>\n<div>\n<div>\n<table>\n<thead>\n<tr>\n<th><strong>Approach<\/strong><\/th>\n<th><strong>When to consider it<\/strong><\/th>\n<th><strong>What needs to be evaluated<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td><strong>Select one material group that addresses both requirements<\/strong><\/td>\n<td>Both wear and adhesion fall within the capabilities of the same material group<\/td>\n<td>May not provide the optimum performance for either requirement individually<\/td>\n<\/tr>\n<tr>\n<td><strong>Combine two material groups<\/strong><\/td>\n<td>Both wear and adhesion are severe or occur in different zones<\/td>\n<td>The interface between the materials must be designed and controlled separately<\/td>\n<\/tr>\n<tr>\n<td><strong>Modify the flow design<\/strong><\/td>\n<td>Angle, cross-section or geometry is the main cause<\/td>\n<td>The problem is no longer purely a material-selection issue<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>The third approach is particularly easy to overlook.<\/p>\n<p>If the root cause lies in flow geometry, changing the material may only <strong>delay the next blockage<\/strong> rather than eliminate the cause.<\/p>\n<p>You can learn more about applications requiring multiple material groups at the same location in <span style=\"color: #3366ff;\"><a style=\"color: #3366ff;\" href=\"https:\/\/giaanh.vn\/en\/knowledge\/combining-multiple-materials-at-one-location-design-principles-and-interface-control\/\"><strong>Part 5: Combining multiple materials at one location: design principles and interface control<\/strong><\/a><\/span>.<\/p>\n<h2><span style=\"color: #970d34;\">8. Changing the sliding angle can help narrow down the cause<\/span><\/h2>\n<p>One test that can help distinguish between a material-related issue and a geometry-related issue is to change the sliding angle, where operating conditions allow.<\/p>\n<p>If increasing the angle does not prevent the material from blocking the flow, the influence of <strong>surface characteristics and lining material<\/strong> should be investigated further.<\/p>\n<p>If increasing the angle restores material flow, the cause is more likely to be related to <strong>flow geometry<\/strong>.<\/p>\n<p>This test does not establish a new design standard.<\/p>\n<p>Its purpose is to help determine whether the investigation should continue toward anti-adhesion material selection or shift toward evaluating the angle, cross-section and configuration of the material flow path.<\/p>\n<h2><span style=\"color: #970d34;\">9. For flow blockage, measure accumulated material rather than only the remaining lining thickness<\/span><\/h2>\n<p>In a wear problem, the important data is the amount of lining material remaining.<\/p>\n<p>For material adhesion, the key data to monitor is <strong>the amount of bulk material that accumulates on the surface<\/strong>.<\/p>\n<p>Four pieces of information should be recorded:<\/p>\n<ul>\n<li>thickness of the build-up layer<\/li>\n<li>time required for the build-up to form<\/li>\n<li>locations where build-up is concentrated<\/li>\n<li>inlet and outlet moisture conditions, together with the actual angle of the sliding surface<\/li>\n<\/ul>\n<p>The build-up area should be shown on a <strong>cross-sectional diagram<\/strong> to illustrate the relationship between the shape of the accumulated material, flow direction and equipment geometry.<\/p>\n<p>If only photographs of the build-up are taken without recording its location, thickness and formation time, the data will be difficult to use for comparison after the solution is changed.<\/p>\n<h2><span style=\"color: #970d34;\">10. Blockage-clearing frequency should be converted into comparable operating data<\/span><\/h2>\n<p>Comments such as \u201cfrequent blockage\u201d or \u201ccontinuous blockage\u201d are not sufficient for evaluating conditions before and after a solution is changed.<\/p>\n<p>Intervention history should be converted into measurable data, for example:<\/p>\n<ul>\n<li>number of blockage-clearing interventions within a defined period<\/li>\n<li>labor time required for each intervention<\/li>\n<li>time between clearing the blockage and the next occurrence<\/li>\n<\/ul>\n<p>This data should be taken from the <strong>operating log<\/strong>, rather than relying only on estimates from operators.<\/p>\n<p>These figures help determine whether a new solution actually changes operating performance or simply delays the next blockage.<\/p>\n<h2><span style=\"color: #970d34;\">11. Responsibilities of each team<\/span><\/h2>\n<div>\n<div>\n<div>\n<table>\n<thead>\n<tr>\n<th><strong>Task<\/strong><\/th>\n<th><strong>Responsible person or team<\/strong><\/th>\n<\/tr>\n<\/thead>\n<tbody>\n<tr>\n<td>Measure moisture, relative adhesiveness and sliding angle, and record seasonal conditions<\/td>\n<td>Survey engineer<\/td>\n<\/tr>\n<tr>\n<td>Provide blockage history and blockage-clearing frequency<\/td>\n<td>Operations supervisor, based on operating logs<\/td>\n<\/tr>\n<tr>\n<td>Assess whether angle and geometry are the main cause<\/td>\n<td>Flow-design engineer<\/td>\n<\/tr>\n<tr>\n<td>Select the appropriate material group when the cause is surface-related<\/td>\n<td>Materials engineer<\/td>\n<\/tr>\n<tr>\n<td>Decide between changing the material, combining materials or modifying the flow design<\/td>\n<td>Operator<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n<\/div>\n<\/div>\n<\/div>\n<p>The role of the engineer assessing flow geometry is particularly important.<\/p>\n<p>Without this step, the problem can easily default to <strong>changing the material<\/strong>, even when the actual cause lies in wall angle, cross-section or the configuration of the material flow path.<\/p>\n<h2><span style=\"color: #970d34;\">12. Notes on applying this knowledge<\/span><\/h2>\n<p><strong>First<\/strong>, the three parameters of moisture, adhesiveness and sliding angle are not covered by a single standard that defines their complete use in this type of application. Any thresholds developed from actual operating data should clearly state their source and scope of application and should not be presented as an industry standard.<\/p>\n<p><strong>Second<\/strong>, sliding tests or assessments are only meaningful when the material conditions are kept consistent. Changes in moisture, particle size or sample condition may make the results no longer directly comparable.<\/p>\n<p><strong>Third<\/strong>, the material group with the highest anti-adhesion performance may not satisfy the other operating conditions at the location. Temperature, impact and wear still need to be checked before the solution is finalized.<\/p>\n<p><strong>Fourth<\/strong>, if flow geometry is the primary cause, changing the lining material does not replace the need to recalculate the angle or cross-section.<\/p>\n<p><strong>Material selection for adhesion-related problems begins by identifying why the bulk material is adhering, not by searching for a harder surface. Only when moisture, surface interaction and sliding angle are considered together is there a technical basis for deciding whether to change the material, combine multiple material groups or address the flow geometry instead.<\/strong><\/p>\n","protected":false},"featured_media":8772,"parent":8485,"menu_order":4,"template":"","meta":{"_acf_changed":false,"inline_featured_image":false},"danh-muc-kien-thuc":[274],"class_list":["post-8489","kien-thuc","type-kien-thuc","status-publish","has-post-thumbnail","hentry","danh-muc-kien-thuc-principles-of-material-selection"],"acf":[],"_links":{"self":[{"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/kien-thuc\/8489","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/kien-thuc"}],"about":[{"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/types\/kien-thuc"}],"up":[{"embeddable":true,"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/kien-thuc\/8485"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/media\/8772"}],"wp:attachment":[{"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/media?parent=8489"}],"wp:term":[{"taxonomy":"danh-muc-kien-thuc","embeddable":true,"href":"https:\/\/giaanh.vn\/en\/wp-json\/wp\/v2\/danh-muc-kien-thuc?post=8489"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}