Effect of porosity: refractory bricks with lower open porosity generally exhibit which of the following property trends?

Introduction / Context:
Porosity is a central design lever in refractories. It influences thermal, mechanical, and corrosion properties. Engineers balance porosity to achieve adequate strength and corrosion resistance while avoiding thermal shock failures and excessive heat losses.

Given Data / Assumptions:

• All other microstructural variables (grain size, bonding) held constant for comparison.
• “Lower porosity” implies higher bulk density.
• We seek the most consistent property trend.

Concept / Approach:
Reducing porosity increases load-bearing area and reduces stress concentrators, typically increasing mechanical strength. Thermal conductivity usually rises with density (pores are thermal barriers), so lower-porosity bricks conduct heat better, not worse. Insulating bricks rely on high porosity; thus, lower porosity means poorer insulation. Heat capacity depends mainly on composition and density; denser bricks often have higher volumetric heat capacity, not lower.

Step-by-Step Solution:
Compare microstructures: fewer/larger solid necks at lower porosity → stronger bricks.Thermal conduction: pores trap gas; reducing pores typically increases conductivity.Insulation: high porosity correlates with better insulation; inverse for low porosity.Choose “Greater mechanical strength” as the most consistent outcome.

Verification / Alternative check:
Standard test data for fireclay, high-alumina, magnesite, and silica bricks show CCS and MOR increasing with density within a given product family.

Why Other Options Are Wrong:
Higher insulating properties: opposite trend; porosity aids insulation.Lower heat capacity: denser bodies carry more heat per unit volume.Lower thermal conductivity: typically the reverse.Always lower corrosion resistance: density often improves corrosion resistance; “always lower” is unfounded.

Common Pitfalls:
Assuming one property (e.g., insulation) improves without tradeoffs; density changes affect multiple properties simultaneously.

Final Answer:
Greater mechanical strength