The term “white metal” is a collective name for a wide range of light-colored metal alloys, not a single material. Determining its magnetic status requires looking closely at its specific elemental makeup. The answer is conditional, depending entirely on the presence or absence of specific elements in the alloy’s formula. This exploration clarifies the magnetic properties of these alloys by contrasting the physics of magnetism with the composition of common white metals.
The Conditional Answer Based on Composition
White metals are generally not magnetic in the common sense. The vast majority of these alloys are composed primarily of elements like tin, lead, zinc, antimony, and copper. None of these base metals exhibit strong magnetic attraction, as a metal’s magnetic response is tied to its atomic structure.
A metal is considered strongly magnetic only if it contains significant quantities of iron, nickel, or cobalt. These three elements are the only ones that naturally possess ferromagnetism at room temperature. Since white metal formulas lack these elements, they are typically classified as either diamagnetic or paramagnetic materials. Diamagnetic materials, such as tin and lead, are weakly repelled by a magnetic field, while paramagnetic materials, such as pure aluminum, are weakly attracted.
Understanding Ferromagnetism
Ferromagnetism is the property responsible for the powerful attraction a material exhibits to a magnet. This behavior originates at the atomic level with the spin of electrons. While most elements have paired electrons that cancel out the magnetic moment, ferromagnetic materials have unpaired electrons whose spins align in the same direction. This alignment gives each atom a small magnetic moment.
Within the metal’s structure, large groups of these atomic magnets spontaneously align, forming microscopic regions called magnetic domains. In an unmagnetized piece of metal, the random orientation of these domains cancels out the overall magnetic field. When an external magnetic field is applied, the domains aligned with the field grow, creating a strong, observable magnetic attraction. This cooperative alignment is unique to the ferromagnetic elements: iron, nickel, and cobalt.
The ability of a material to maintain this magnetic alignment disappears above the Curie point. Once heated past this point, thermal energy overcomes the forces holding the domains in alignment, and the material temporarily loses its ferromagnetic properties. This mechanism explains why the non-ferromagnetic components of white metal alloys cannot be made into permanent magnets.
Common Alloys Labeled as White Metal
The term “white metal” is broadly applied to several distinct alloys, each with a different primary component and use.
Pewter
Pewter is a common white metal, traditionally composed of 85–99% tin, with small additions of copper and antimony to increase strength. Since tin is the dominant element and is not ferromagnetic, pewter does not stick to a magnet.
Babbitt Metal
Babbitt metal, or bearing alloys, are used industrially as a lining for bearings due to their low friction properties. These are typically tin-based or lead-based alloys, containing antimony and copper. Since both tin and lead are non-ferromagnetic, these industrial white metals are not attracted to a magnet.
Zinc-Based Alloys
Zinc-based alloys, often referred to as pot metal or die-cast alloys, are also considered white metals. They are commonly used in costume jewelry and small components. Zinc is a diamagnetic material and is therefore not magnetic. The only scenario where a white metal object might appear magnetic is if it is a piece of jewelry with a thin white metal plating over a core made of steel, which contains iron.