“If you look at the practical fields of application and the specific functionality that silicon carbide may deliver in these fields, then what we are actually selling to our customers when using our SiC products, is a guarantee for problem solving” Thiemo Schertler, Sales Manager at 3M Technical Ceramics in Kempten, sums it up. This is a bold statement – yet it is one, which Schertler can back up with many years of experience in the use of silicon carbide (“SSiC” or “SiC” short form) in the broad fields of application among its customers: “We serve companies here that use our materials for their specific purposes for decades. With correct layout, SiC delivers the expected performance for its specific function and reliability meets the high demands of our customers – for new and existing likewise.”
Reliability and durability are attributes that are reflected in the high resilience and consequently long maintenance intervals for the components: for Schertler, these are the main arguments that justify the use of this high-quality ceramic material in a plurality of application fields. The advantage is: “Even potential new customers virtually take no risk. We offer the opportunity of talking to our customer project management team to check whether the use of silicon carbide is indeed an option for use in your component.”
Depending on the properties that play a role for the individual user, SiC has a broad range of applications that extends across industries. The material is widely used in process engineering in the area of industrial pumps, especially for plain bearings and mechanical seals. SiC is also used in oil and gas refineries, in underwater applications and in the chemical and pharmaceutical industry. Thomas Thiele, Key Account Manager at 3M Technical Ceramics, explains it: “When operating pumps, for example, the worst-case scenario is a breakdown of the system. In order to prevent such an incident, which may arise from the use of less suitable materials for example, operators will always be on a safe side by choosing a material that reduces such a risk to a minimum.”
The special material properties that may be advantageous to the respective assembly using SiC are in particular:
1. Chemical resistance and wear resistance
SiC has an extremely high corrosion resistance and shows minimal wear in the presence of abrasive media. “One should always check options to use sintered silicon carbide for example for components that are exposed to particle loaded media or highly aggressive chemical substances, presupposing maximum operational reliability at the same time,” advises Ulrich Dirr, Customer Project Management specialist at 3M Technical Ceramics. “These material properties offer maximum safety for the end-user and finally for the environment,” says Dirr – a convincing argument.
2. Temperature resistance and thermal conductivity
SiC materials show an enormous resilience and extraordinarily high dimensional stability even in applications that are carried out at high and extremely high temperatures. In this regard, silicon carbide is one of the most efficient industrial materials on the market. SiC’s high temperature resistance together with its exceptional thermal conductivity is a combination that is often required. An example of this is temperature measurement under extreme environmental conditions, where SiC acts as a protective housing for sensitive sensors when performing measurements in process gases contaminated with ashes. The silicon carbide housing not only protects the sensors very effectively against the abrasive particles, it also enables temperature measurements of high precision and response time.
3. Mechanical strength and hardness
The combination of relatively high strength and relatively low density compared to metallic materials makes SiC the ideal construction material for applications in lightweight designs.
Dirr explains: “Most of our existing or potential new customers come to us because of previous poor experiences they have had. The materials used to date – which are mostly metals – either fail to achieve the desired performance for their application or the company´s entitlements, or they do not meet end customers’ constantly increasing demands for quality. The reasons for this are an insufficient lifespan, heavy wear or chemical attack from the corresponding component – and the consequences of these when operating the respective system. Such consequences range from undesired contamination of the product in subsequent process steps due to undesired foreign particles up to clogged filters or even until complete failure and downtime of the entire production chain.”
According to 3M’s Thiele, this applies not only to the use of materials made of metal or plastic, but also to less suitable materials under certain load configurations. “We currently have a customer who used tungsten carbide for their plain bearings. Over the course of the service life, it turned out that this metallic material does not meet the expected resilience and durability in the component. As a result, the customer was looking for a more efficient long-term solution that would reduce the risk of breakdown to an absolute minimum. The use of a silicon carbide component proved to be the right solution for their purposes!”
Ulrich Dirr believes that there are two parameters which are particularly significant for the use of SiC materials: “We check exactly in which environment the silicon carbide is used, which functions it should perform there and how crucial this function would be for the entire system. The more important the role of the component is to operation and functionality, the more the use of this material will pay off.”
An experienced technical consultant can usually quickly determine whether the desired requirements with regards to wear, abrasion or heat resistance can be achieved by the use of SiC ceramics, even during initial discussions with non-specialist customers.
For example, under the “3MTM Sintered Silicon Carbide Family” product portfolio, 3M Technical Ceramics offers different sintered silicon carbides which are optimally adapted to specific application requirements.
3M Silicon Carbide Grade F: A fine-grained, dense SiC, the all-rounder for bearings and seals
3M Silicon Carbide Grade C: A coarse-grained, dense SiC, the specialist for extreme corrosive environments
3M Silicon Carbide Grade G: A graphite loaded composite, the specialist for sliding and friction systems with a focus on dry run
3M Silicon Carbide Grade P: A defined porous grade, a second specialist for sliding and friction systems with a focus on dry run
3M Silicon Carbide Grade T-plus: A fine-grained, dense composite with a glassy phase, the specialist for complex thermal and mechanical loads
A component drawing is essential for determining feasibility in a specific case. Once all the relevant information has been shared – requirements, dimensions, quantities, target price – the technical expert provides the potential customer with a basis for decision-making. Based on this, the customer can then precisely assess whether the use of sintered ceramics will provide the added value he was looking for.
Regardless of their decision, whether they end up using technical ceramics or not, the time invested into seeking advice is in any event time well spent!
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