Difference Between Thixotropic and Rheopectic Fluids

Thekey differencebetween thixotropic and rheopectic fluids isthat in thixotropic fluids, theviscosityof the fluid decreases withstressover time whereas, in rheopectic fluids, the viscosity of the fluid increases with stress over time.

流体是具有粘度的液体或气态物质。我们可以将流体分为两种类型的粘度，例如触变性和风湿性流体。但是，这两个都是non-Newtonian fluids. Also, these are considered as rare fluids.

1.Overview and Key Difference
2.What are Thixotropic Fluids
3.What are Rheopectic Fluids
4.Side by Side Comparison – Thixotropic vs Rheopectic Fluids in Tabular Form
5.概括

What are Thixotropic Fluids?

触变流体是液体或气体，其粘度在已知的时间段内施加应力后会降低。因此，它可以定义为时间依赖性的假性塑性行为。相比之下，风湿性流体的行为可以描述为时间依赖性的扩张性行为。这些流体也显示出非线性应力 - 应变行为。因此，液体在剪切应力下的时间越长，液体的粘度降低。换句话说，当引入剪切速率变化时，这些流体需要一些时间才能获得其粘度平衡。

Some common examples of thixotropic fluids include cytoplasm of cells, synovial fluid, some varieties of honey, some types of clay, solder pastes in electronics, thread-locking fluids, gelatin, xanthan gum, etc.

What are Rheopectic Fluids?

Rheopectic fluids are liquids or gases whose viscosity of the fluid increases with stress over time. The behaviour of these fluids can be described as a time-dependent dilatant behaviour. Thus, these fluids are a rare class of non-Newtonian fluids. Also, they show an increased viscosity upon agitation. That means, when the fluid is shaken, it becomes thick, or it may even solidify. Moreover, higher the shear stress, more viscous that fluid becomes. It is because the microstructure of these rheopectic fluids is constructed under continuous shearing. Therefore, it is named as shear-induced crystallization. Some common examples of rheopectic fluids include some gypsum pastes, printer ink, lubricants, etc.

What is the Difference Between Thixotropic and Rheopectic Fluids?

流体是具有粘度的液体或气态物质。We can divide fluids into two types based on the viscosity: thixotropic and rheopectic fluids. The key difference between thixotropic and rheopectic fluids is that in thixotropic fluids, the viscosity of the fluid decreases with stress over time whereas, in rheopectic fluids, the viscosity of the fluid increases with stress over time.

触变流体的一些示例包括细胞的细胞质，滑液，某些蜂蜜，某些类型的粘土，电子产品中的焊料，螺纹锁定液，明胶，黄质胶等。石膏糊，打印机墨水，润滑剂等。此外，触变流体的行为可以描述为时间依赖性的假性塑性行为。然而，风湿性流体的行为可以描述为时间依赖性的扩张剂行为。

The following table summarizes the difference between thixotropic and rheopectic fluid.

概括– Thixotropic vs Rheopectic Fluids

Fluids are liquid or gaseous substances which have a viscosity. We can divide fluids into two types based on the viscosity as thixotropic and rheopectic fluids. The key difference between thixotropic and rheopectic fluids is that in thixotropic fluids, the viscosity of the fluid decreases with stress over time whereas, in rheopectic fluids, the viscosity of the fluid increases with stress over time.

Reference:

1. “Non-Newtonian Fluids: Rheopectic vs. Thixotropic.” Materials, 4 Aug. 2016,Available here.
2. “Rheopecty.” Wikipedia, Wikimedia Foundation, 5 Mar. 2020,Available here.
3.“时间粘度。”维基百科,Wikimedia Foundation, 8 Nov. 2019,Available here.