Amalgam (chemistry) Amalgam (chemistry) An amalgam is an alloy of mercury with another metal, which may be a liquid, a soft paste or a solid, depending upon the proportion of mercury. These alloys are formed through metallic bonding, with the electrostatic attractive force of the conduction electrons working to bind all the positively charged metal ions together into a crystal lattice structure. Almost all metals can form amalgams with mercury, the notable exceptions being iron, platinum, tungsten, and tantalum. Silver-mercury amalgams are important in dentistry, and gold-mercury amalgam is used in the extraction of gold from ore. Zinc amalgam finds use in
Amalgam (dentistry) problem. This phase has been shown to be the weakest phase in the set amalgam and is subject to corrosion, particularly at the tooth-amalgam interface. In 1962 a new amalgam alloy, called Dispersalloy, was introduced with the addition of a spherical silver-copper eutectic particle to the traditional lathe-cut AgSn particle in a ratio of 1:2. The mixture of these two types of particles is known as admix alloy. The benefits of this alloy was to strengthen the set amalgam and reduce the γ phase (SnHg). The increased copper in the silver-copper eutectic reacted preferentially with tin so that SnHg could